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SAFETY 


GIFT  OF 


COPYRIGHT  BY  WILL  H.  LOW. 


ICARUS 

From  a  mural  painting  by  Will  H.  Low,  in  the  New  York  State 
Education  Building,  Albany,  New  York. 


Airplanes 

and 

Safety 


"Soon  shall  thy  arm^  un conquered  Steam,  afar 
Draw  the  slow  barge,  or  drive  the  rapid  car; 
Or,  on  wide  waving  wings  expanded,,  bear 
The  flying  chariot  through  the  field  of  air" 

Erasmus  Darwin.     [1781] 


THE  TRAVELERS 

HARTFORD,        CONNECTICUT 


22031     4-13-21 


Copyright,  1921,  by 

THE  TRAVELERS  INSURANCE  COMPANY, 

Hartford,  Connecticut 


GIFT 


PREFACE 


T^EFORE  aircraft  can  be  extensively  utilized  for 
J~J  -private  and  commercial  purposes^  and  before  aerial 
navigation  can  be  developed  to  a  point  where  it  will  afford 
an  attractive  field  to  insurance  companies^  it  will  be 
necessary  to  effect  a  substantial  readjustment  of  present- 
day  conditions.  The  public^  for  example^  will  have  to 
acquire  a  considerable  amount  -of  aeronautical  knowledge 
before  it  will  be  prepared  to  admit  the  practicability  of 
aerial  navigation.  There  is  also  a  crying  need  for  a 
vastly  greater  number  of  official  landing  fields  >  laid  out  and 
managed  in  accordance  with  approved  safety  principles. 
It  is  likewise  necessary  to  establish  standard  airways^ 
duly  provided  with  aerial  lighthouses  and  wireless  signal 
stations;  and  to  pass  uniform  and  stringent  laws  govern- 
ing the  licensing  of  pilots^  the  construction  and  use  of  air- 
craft3  and  the  conduct  of  air-navigation  generally. 

In  the  present  stage  of  development  it  is  impossible 
to  discuss  the  subject  of  "AIRPLANES  AND  SAFETY" 
exhaustively  and  fully  ^  and  the  present  book  does  not 
attempt  to  do  so.  We  are  putting  it  forth ,  however •,  in  the 

' 7 

456657 


VI  AIRPLANES  AND  SAFETY 

belief  that  it  will  assist  in  promoting  aerial  navigation  by 
presenting  an  elementary  account  of  the  construction  and 
operation  of  airplanes,  and  by  discussing  some  of  the 
means  by  which  flying  may  be  made  a  safer  mode  of  travel 
and  transportation. 

Rapid  changes  of  many  kinds  are  inevitable  in 
connection  with  so  new  a  subject, — changes  relating  not 
only  to  apparatus,  but  also  to  the  training  and  licensing 
of  pilots,  to  the  insurance  coverage,  to  the  legal  aspect,  and 
to  many  other  phases.  With  increasing  study  and  ex- 
perience the  subject  is  sure  to  develop  quickly,  and  it  is 
quite  within  the  range  of  possibility  that  fundamental 
modifications  along  any  of  these  lines  may  be  forthcoming 
within  a  year  or  two.  If  we  had  the  gift  of  prophecy  we 
should  include  all  these  future  advances  and  improvements 
in  the  present  book.  Not  having  any  such  gift,  however, 
we  have  merely  endeavored  to  represent  the  subject  as  it 
stands  to-day. 

The  text  is  based  primarily  upon  our  own  experience 
and  observation,  though  we  have  naturally  consulted 
numerous  books,  pamphlets,  reports,  and  technical  jour- 
nals. Furthermore,  we  have  had  friendly  personal  coun- 
sel from  many  eminent  and  qualified  sources,  and  notably 
from  Colonel  E.  A.  Deeds '  of  the  Equipment  Division, 
Air  Service,  U.  S.  Army;  from  Lieut. -Colonel  H.  M. 
Hickam,  Major  E.  L.  Jones,  and  L.  D.  Seymour,  M.  E., 
of  the  Information  Group,  Office  of  the  Director  of  Air 
Service;  from  Lieut. -Commander  Eyrd  and  Mr.  Lane 
Lucy,  of  the  Navy  Department;  from  Second  Assistant 
Postmaster  General  Otto  Prager;  and  from  Nelson  S. 
Hopkins,  President  of  the  Phenix  Aircraft  Products 
Company.  But  although  we  desire  to  express  our  fullest 
appreciation  of  the  generous  assistance  we  have  received 


PREFACE  Vll 

from  these  gentlemen,  it  must  be  clearly  understood  that 
they  have  acted  only  in  an  advisory  capacity ',  and  that  they 
are  not  in  any  way  responsible  for  the  statements  that  are 
made.  The  responsibility  is  wholly  our  own,  and  we 
accept  it  in  full. 

THE   TRAVELERS  INSURANCE    COMPANY 

THE  TRAVELERS  INDEMNITY  COMPANY 

HARTFORD,  CONNECTICUT 


CONTENTS 

Introduction: 

The  Legend  of  Icarus I 

Early  Balloons .  3 

The  Beginnings  of  the  Airplane 6 

Influence  of  the  World  War 9 

The  Future  of  Aerial  Navigation 1 1 

Commercial  Uses  of  Aircraft 1 1 

I.  Airplane  Construction: 

Types  of  Machines 13 

Aeronautical  Engines 18 

The  Structural  Parts  of  Airplanes 18 

The  Body 19 

The  Wings 19 

The  Tail 23 

The  Landing  Gear 24 

Structural  Materials  Used 25 

Control 29 

Plan  and  Performance 31 

II.  The  Operation  of  Airplanes: 

Introductory 36 

Tuning-up 36 

Standard  Clothing  and  Equipment 41 

III.  Airplane  Accidents: 

General  Causes  of  Accidents  ........  43 

Errors  of  the  Pilot 45 

Failure  of  the  Machine 47 

Fire 47 

Superchargers  and  Variable-pitch  Propellers      ...  52 

Instruments 52 

Safety  Straps 54 

Emergency  Stations 55 


X  AIRPLANES  AND  SAFETY 

IV.  Pilots: 

The  Importance  of  Legal  Regulation 57 

Physical  and  Mental  Qualifications  of  Pilots     ...  58 

Training 61 

Examination  and  Licensing 63 

Care  of  the  Pilot's  Health 64 

V.  The  Maintenance  and  Repair  of  Airplanes: 

The  Repair  Shop 67 

Repair  Shop  Hazards 69 

General  Fire  Prevention 70 

Woodworking 71 

Doping .  73 

Machine  Shop 76 

Motor  Testing 78 

VI.  Landing  Fields,  Airways,  and  Aerial  Laws: 

Landing  Fields  in  General 79 

Airdromes 79 

Emergency  Fields 85 

Airways  and  Air  Routes 85 

-  Aerial  Laws 86 

VII.  Meteorological  Service 89 

VIII.  Aircraft  Insurance: 

Limited  Character  of  the  Field 91 

The  Development  of  Transportation 92 

Possibilities  and  Limitations  of  Aircraft 93 

The  Dangers  of  Aerial  Transportation 95 

Making  Insurance  Rates 96 

Unreliability  of  the  Airplane 97 

The  Cost  of  Airplanes 98 

Why  Should  Aircraft  be  Insured? 99 

Nature  of  the  Insurance  Contracts 101 

The  Future  of  Aerial  Navigation 104 

Glossary  of  Aviation  Terms 107 


ILLUSTRATIONS 

Icarus Frontispiece 

The  Reconstructed  Langley  "Aerodrome" 8 

A  Non-rigid  Dirigible  or  Blimp 14 

An  Airplane 16 

A  Hydroairplane 17 

A  Flying  Boat 18 

Diagram  Showing  the  Parts  of  an  Airplane      .....  22 

An  All-metal  Monoplane 27 

An  All-metal  Biplane 28 

Sand-testing  an  Airplane  Wing 33 

Airplane  after  Turning  Turtle 44 

A  Result  of  Deficient  Vision 46 

A  Typical  Airplane  Fire 49 

Testing  a  Candidate's  Eyes 59 

An  Orientator  in  Action 62 

The  Crash  in  which  Resnati  met  his  Death  at  Mineola     .      .  65 

Testing  a  Landing  Gear 68 

Sand-testing  a  Fuselage 69 

A  Well-regulated  Workshop 71 

Testing  an  Engine 77 

Specifications  for  Landing  Fields  and  Field  Markers        .      .  80 

An  Airdrome,  Showing  Wind  Indicators 82 

The  Type  of  Wind-cone  used  at  Curtiss  Field       ....  83 

A  Well-arranged  Airdrome    ....'......  84 

An  Aerial  Lighthouse 87 

A  Seaplane  Crash 100 

After  the  Accident 100 

An  Airplane  that  Fell  in  a  City  Street 102 


Airplanes 

and 

Safety 

INTRODUCTION 


THE  LEGEND  OF  ICARUS:  Men  dreamed  of 
navigating  the  air  long  before  any  means  were 
devised  for  realizing  such  dreams.  Legends,  some  of 
which  run  back  into  remote  antiquity,  tell  of  men  who 
succeeded  in  rising  into  the  air  by  one  means  or  another, 
—the  best  known  story  of  this  kind  being  the  one  in 
which  Daedalus  and  Icarus  figure.  It  may  be  remem- 
bered that  Daedalus,  who  was  a  talented  Greek  inventor, 
fled  for  certain  reasons  to  the  Island  of  Crete,  where  he 
constructed  a  famous  labyrinth  for  King  Minos,  pre- 
sumably about  the  year  2000  B.  C.  Subsequently, 
Daedalus  was  himself  imprisoned  in  this  labyrinth, 
together  with  his  son  Icarus;  and  we  are  told  that  they 
saved  up  the  feathers  that  fell  into  their  prison  from 
birds  passing  overhead,  and  eventually  fashioned  these 
feathers  into  wings,  by  means  of  which  they  effected 
their  escape.  Daedalus  told  Icarus  to  keep  up  high 
enough  to  avoid  the  dampness  from  the  sea,  but 
warned  him  not  to  fly  too  near  the  sun  lest  the  heat  from 
it  melt  the  wax  by  which  the  feathers  in  his  wings  were 
held  together.  The  young  man  disregarded  the  latter 


2  INTRODUCTION 

part  of  this  counsel,  however,  and  the  accident  that 
his  father  had  foreseen  came  to  pass.  He  flew  too 
high,  the  wax  softened,  the  wings  became  unmanage- 
able, and  the  youthful  aviator  fell  into  the  sea  and  was 
drowned.  Tradition  even  records  the  place  of  his  fall, 
locating  it  near  the  island  of  Samos;  and  the  part  of  the 
Aegean  Sea  in  that  vicinity  is  still  called  the  Icarian  Sea. 
According  to  this  evidence,  the  young  man  must  have 
flown  something  like  200  miles  before  he  came  to  grief. 
The  father  escaped  in  safety,  and  eventually  reached 
Sicily. 

Every  legend  probably  has  some  measure  of  founda- 
tion in  fact,  but  in  the  case  of  Icarus  it  would  be  hard  to 
identify  the  elements  of  reality,  and  separate  them  from 
the  frills  and  wrinkles  that  forty  centuries  have  added. 
The  labyrinth  to  which  the  story  refers  has  recently 
been  discovered  and  explored,  and  we  also  know  that 
Crete,  in  the  time  of  Minos  arid  Daedalus,  was  one  of 
the  world's  most  influential  and  important  centers  of 
progress  and  civilization.  All  this,  however,  proves 
nothing  about  the  reality  of  the  overseas  flight  of 
Icarus.  The  most  realistic  and  probable  element  of  the 
tale,  from  our  point  of  view,  is  the  disregard  that  Icarus 
showed  for  the  safety  advice  that  his  father  gave  him. 
The  older  man  was  an  experienced  mechanic  and  in- 
ventor, who  realized  that  accidents  are  likely  to  happen, 
and  who  was  thoughtful  enough  to  consider,  in  advance, 
how  safety  could  best  be  assured.  But  the  younger 
man,  just  like  millions  of  others  down  to  the  present  day, 
let  the  counsel  pass  in  at  one  ear  and  out  at  the  other; 
and  when  he  was  soaring  up  into  the  sky  he  "took  a 
chance,"  and  almost  immediately  thereafter  he  was 
killed.  That  doesn't  sound  the  least  bit  like  forty 


EARLY    BALLOONS  3 

centuries  ago.     It  sounds  more  like  last  Wednesday 
afternoon,  in  the  little  shop  across  the  street. 

Mr.  Will  H.  Low  has  painted  a  beautiful  panel  in 
the  New  York  State  Education  Building,  depicting  the 
fall  of  Icarus;  and  by  special  permission  of  the  artist 
and  the  New  York  State  Education  Department  we 
have  used  a  photo-engraving  of  it  as  the  frontispiece 
of  this  book.  The  modern  airplane,  high  up  in  the 
sky  of  the  painting,  typifies  the  success  that  has 
finally  followed  in  the  wake  of  so  many  years  of  dream- 
ing and  experimenting.  The  body  of  Icarus  lies  upon 
the  rocky  shore  where  it  has  been  cast  up  by  the  sea,— 
the  nearness  of  which  is  suggested,  or  symbolized,  by 
the  water  in  the  immediate  foreground. 

EARLY  BALLOONS:  Passing,  now,  .from  legend 
to  history,  we  find  that  the  first  successful  at- 
tempt to  navigate  the  air  was  made  in  France,  by  two 
brothers,  Stephen  and  Joseph  Montgolfier.  Toward 
the  end  of  1782  they  had  found  that  light  bags  would 
ascend  if  filled  with  heated  air,  and  on  June  5,  1783, 
they  gave  a  public  exhibition  near  Lyons,  in  the  course 
of  which  a  linen  globe  more  than  thirty  feet  in  diameter 
was  inflated  with  hot  air  and  liberated.  It  rose  to  a 
great  height,  remained  in  the  air  about  ten  minutes, 
and  came  down  again  about  a  mile  and  a  half  from  the 
starting  point.  This  experiment  naturally  attracted 
a  great  deal  of  attention,  and  the  French  physicist 
J.  A.  C.  Charles,  realizing  that  a  hot  air  balloon  would 
be  impracticable  except  for  extremely  short  flights, 
suggested  that  the  necessary  levity  be  obtained  by 
filling  the  bag  with  hydrogen  gas  (which  was  then 
called  "inflammable  air").  The  money  required  for 


INTRODUCTION 


testing  the  practicability  of  the  idea  was  raised  by 
popular  subscription;  and  on  August  27,  1783,  a 
gas-filled  balloon,  thirteen  feet  in  diameter,  constructed 
by  the  Robert  brothers  under  the  direction  of  Charles, 
ascended  from  the  Champ-de-Mars,  Paris.  It  rose 
to  a  height  of  3000  feet  and  remained  in  the  air  for 
three  quarters  of  an  hour. 

On  September  19,  1783,  Joseph  Montgolfier  sent 
up  another  hot-air  balloon  at  Versailles  in  the  presence 
of  the  King  and  Queen  and  a  vast  assemblage  of  other 
spectators,  and  on  this  occasion  a  cage  was  taken  up, 
containing  a  sheep,  a  rooster,  and  a  duck.  The  rooster 
and  the  duck  behaved  themselves  with  due  dignity, 
but  the  sheep,  failing  to  understand  that  it  was  about 
to  become  famous  as  a  member  of  the  first  party  of 
living  creatures  to  go  up  in  a  balloon,  or  not  appreciat- 
ing the  honor  thus  thrust  upon  it,  kicked  the  rooster 
just  before  the  start,  and  injured  it  somewhat.  The 
ascent  was  made  successfully,  however,  and  without 
further  harm  to  the  creatures  in  the  cage,  although  they 
ascended  to  a  height  of  about  1500  feet  and  came  down 
two  miles  from  the  starting  point,  after  a  trip  lasting 
eight  minutes. 

The  practicability  of  making  a  balloon  ascent 
being  thus  demonstrated,  men  were  soon  found  who 
were  willing  to  take  the  attendant  risks.  The  first 
human  being  to  ascend  was  Jean  Francois  Pilatre  de 
Rozier,  who  went  up  in  a  captive  balloon  on  October 
15,  1783,  with  a  lighted  brazier  suspended  below  the 
bag  to  keep  the  air  heated.  After  a  number  of  ex- 
periences of  this  kind  he  ventured  to  go  up  in  a  free 
fire  balloon,  on  November  21,  1783,  in  company  with 
the  Marquis  d'Arlandes,  They  remained  in  the  air  more 


EARLY    BALLOONS  5 

than  twenty  minutes,  and  came  down  safely  after 
drifting  more  than  five  miles. 

Ten  days  later  (namely,  on  December  i)  Charles, 
the  physicist  whom  we  have  already  mentioned, 
ascended  from  Paris,  accompanied  by  one  of  the 
Robert  brothers,  in  a  balloon  filled  with  hydrogen. 
The  two  men  were  in  the  air  about  two  hours,  and 
landed  some  twenty-seven  miles  from  the  starting 
point.  Robert  then  left  the  car,  and  Charles  made  a 
second  ascent  alone,  rising  on  this  occasion  to  a  height 
of  about  two  miles. 

Honorable  mention  must  be  made,  at  this  point, 
of  Rittenhouse  and  Hopkinson,  of  Philadelphia,  who 
were  experimenting  with  balloons  almost  as  early  as 
the  Montgolfiers,  and  who  also  constructed  a  successful 
gas-filled  balloon  of  the  composite  type,  in  which 
James  Wilcox  made  an  ascent. 

Girond  de  la  Villette,  who  had  accompanied  de 
Rozier  in  one  of  his  early  ascents,  proposed  to  employ 
balloons  in  warfare;  and  in  1794  a  French  company 
of  "aerostiers"  was  formed,  an  air-park  was  established, 
and  balloon  reconnaissances  were  actually  made  against 
the  Austrians.  Balloons  were  used  extensively  for 
observation  work  during  the  siege  of  Paris,  in  1870-71. 
They  were  also  used  in  considerable  numbers  in  our 
own  War  between  the  States,  and  in  the  Spanish  War 
of  1898,  and  the  Russo-Japanese  War.  All  these 
military  balloons  were  of  the  spherical  type,  and  were 
moored  to  the  ground  by  means  of  cables.  The  modern 
stream-lined  observation  balloon  was  not  developed 
until  a  few  years  prior  to  1914,  but  before  the  close 
of  the  World  War,  it  had  practically  displaced  all 
other  means  of  directing  artillery  fire. 


6  INTRODUCTION 

THE  BEGINNINGS  of  the  Airplane:  The  first 
steps  towards  the  development  of  the  heavier-than- 
air  flying  machine — that  is,  of  the  type  of  aircraft  that 
has  no  supporting  gas-bag — may  be  assigned  to  various 
periods,  according  to  the  views  that  we  may  hold  with 
regard  to  what  constitutes  a  first  step.  If  we  chose  to 
go  back  to  the  most  elementary  principles  of  mechanical 
flight,  in  which  other  elements  than  mere  momentum  are 
utilized  for  keeping  the  apparatus  in  the  air,  it  would 
doubtless  be  necessary  to  credit  the  prehistoric  aborigi- 
nes of  Australia  with  the  earliest  invention,  because  the 
boomerang  certainly  involves  some  of  the  principles  that 
underlie  the  operation  of  the  modern  airplane.  If,  on 
the  other  hand,  we  are  to  pass  over  the  boomerang,  as 
well  as  the  kite  (including  the  scientific  species  as  well  as 
the  juvenile  one),  and  the  various  small-sized  "helicop- 
ters" and  other  toy-like  devices  that  have  appeared  from 
time  to  time,  and  are'  to  begin  our  survey  with  the  earl- 
iest form  of  apparatus  that  held  out  distinct  promise  of 
an  actual,  early  solution  of  the  problem  of  navigating 
the  air  with  a  heavier-than-air  mechanism,  we  shall 
have  come  down  to  the  latter  part  of  the  Nineteenth 
Century,  when  Lilienthal,  Chanute,  Pilcher,  the  Wright 
brothers,  and  many  others,  laid  the  foundation,  by 
means  of  their  gliding  planes,  for  the  rapid  development 
of  the  art  in  a  useful  and  practical  direction. 

Dr.  Samuel  Pierpont  Langley,  Secretary  of  the 
Smithsonian  Institution,  will  always  be  regarded  as 
the  first  to  establish  the  principles  of  mechanical  flight 
upon  a  sound  scientific  basis.  He  began  his  serious 
work  along  this  line  about  the  year  1887,  publishing 
his  "Experiments  in  Aerodynamics"  in  1891,  and  "The 
Internal  Work  of  the  Wind"  in  1894. 


EARLY    AIRPLANES  7 

Sir  Hiram  Maxim  constructed  an  enormous  steam- 
driven  airplane  in  1894,  for  experimental  purposes. 
It  was  supposed  to  be  confined  to  a  long  track  that 
was  erected  for  the  purpose,  but  it  tore  loose,  left  the 
track,  wrecked  itself,  and  was  never  rebuilt. 

Langley  built  a  quarter-size  steam-driven  airplane 
which  made  a  sustained  flight  over  the  Potomac  river 
near  Washington,  D.  C.,  on  May  6,  1896.  Encouraged 
by  this  result,  he  afterward  constructed  a  full-sized 
machine,  also  driven  by  steam,  and  flights  were  at- 
tempted near  Washington  on  October  7,  1903,  and 
again  on  December  8.  Owing  to  mishaps  in  launching, 
the  machine  fell  into  the  Potomac  on  both  occasions, 
and  on  the  second  trial  it  was  wrecked  by  the  poorly- 
directed  efforts  of  a  tug  to  rescue  it.  The  failure  of 
the  experiment  was  witnessed  by  hundreds  of  news- 
paper correspondents,  who  published  supposedly  hu- 
morous accounts  of  the  proceedings,  and  the  ridicule 
caused  Congress  to  refuse  further  contributions  toward 
the  work,  and  also  had  a  profound  effect  upon  Langley 
himself,  so  that  many  believe  that  it  hastened  his 
death.  The  machine  was  raised  and  placed  on  exhibi- 
tion in  the  Smithsonian  Institution.  In  recent  years 
it  has  been  repaired,  and  after  being  provided  with 
new  wings  and  with  a  gasoline  engine,  it  has  been 
successfully  flown, — the  soundness  of  Langley's  general 
design  being  thereby  proved. 

In  1903  Wilbur  and  Orville  Wright  built  a  self- 
propelled  machine  in  which  they  used  a  twelve-horse- 
power gasoline  engine  and  two  propellers.  Their  first 
successful  flight  with  this  design  was  made  on  Decem- 
ber 17,  1903.  In  1904  and  1905  they  made  many 
flights,  some  in  public  and  some  in  private.  They 


8  INTRODUCTION 

Photo  by  Benner. 


THE  RECONSTRUCTED  LANGLEY  "AERODROME." 

originally  undertook  their  aerial  experiments  out  of 
pure  scientific  interest,  and  with  no  thought  of  a 
possible  commercial  return.  As  their  investigations 
proceeded,  however,  they  became  so  absorbed  in  the 
subject  that  they  gave  up  all  other  business  and  de- 
voted themselves  solely  to  their  aircraft  researches. 
In  the  winter  of  1907-8  the  U.  S.  Signal  Corps  called 
for  bids  on  an  airplane  and  an  airship,  and  the  Wright 
brothers  undertook  to  comply  with  the  conditions  and 
deliver  a  practical  airplane.  With  this  in  view  they 
did  a  great  amount  of  experimental  work  during  1908, 
and  in  the  fall  of  that  year  they  began,  at  Washington, 
a  series  of  demonstration  flights  which  terminated  in  the 
unfortunate  death  of  Lieut.  Selfridge,  who  was  a  pas- 
senger with  Orville  Wright.  Delivery  of  the  machine  to 
the  United  States  Government  was  finally  made  in  1909. 
The  pioneer  flights  made  by  the  Wright  brothers 
in  1904  and  1905  were  followed  in  1908  by  the  work  of 
the  Aerial  Experiment  Association,  composed  of  Dr. 


INFLUENCE    OF    THE    WORLD    WAR  9 

A.  G.  Bell,  Glenn  Curtiss,  Lieut.  Thomas  E.  Selfridge, 
F.  W.  Baldwin,  and  J.  A.  D.  McCurdy,  and  by  the 
flights  of  Curtiss  in  his  own  machine  in  1909. 

The  achievements  of  Langley,  the  Wright  brothers, 
and  Curtiss,  gave  to  the  United  States  the  distinction 
of  being  unquestionably  the  first  country  in  the  world 
to  build  what  were  conceded  to  be  successful  airplanes. 

INFLUENCE  of  the  World  War:  From  the  begin- 
nings here  outlined,  progress  was  slow.  At  the 
outset  there  was  practically  no  demand  for  airplanes, 
and  the  few  that  were  used  for  sport  were  of  a  prim- 
itive type.  The  United  States  Army  did  a  little  flying, 
but  no  serious  attempt  was  made  to  develop  this 
branch  of  the  service  until  1914.  Five  officers  of  the 
United  States  Army  were  then  sent  to  the  Massachu- 
setts Institute  of  Technology  to  study  aeronautics,  and 
in  August,  1914,  these  five  men  constituted  the  entire 
technically-trained  personnel  of  our  Army  air  service, 
though  there  were,  in  all,  twenty-four  officers  and  one 
hundred  and  fifteen  enlisted  men  on  aeronautical  duty 
on  that  date. 

The  problem  that  confronted  the  United  States 
in  connection  with  aerial  navigation  at  the  time  we 
entered  the  World  War  was  a  staggering  one.  With 
no  stock  of  material,  and  with  practically  no  personnel 
experienced  in  airplane  designing,  and  with  an  utter 
lack  of  knowledge  of  the  requirements  of  the  most 
advanced  aircraft  for  war  purposes,  or  of  the  appliances 
essential  to  their  operation,  the  government  faced  a 
serious  situation.  But  the  war  brought  forth  marvelous 
unrealized  resources,  both  of  materials  and  of  technical 
knowledge,  and  in  spite  of  contradictory  opinion,  the 


IO  INTRODUCTION 

development  of  our  Air  Service  reflects  the  greatest 
credit  upon  the  men  who  handled  the  situation;  and 
if  the  war  had  continued  six  months  longer,  the  United 
States  would  have  supplied  more  airplanes  than  all 
of  our  Allies  combined.  At  the  time  of  the  armistice, 
some  of  our  heavy  planes  were  already  superior  in  de- 
sign to  those  of  European  make. 

By  the  co-operation  of  the  manufacturers  in  this 
country,  and  with  the  assistance  of  our  European 
Allies,  flying  fields  and  training  schools  were  developed 
and  engines  and  planes  were  perfected  with  great 
rapidity;  and  at  the  end  of  the  World  War  our  air 
forces  numbered  nearly  200,000,  including  20,708 
trained  officers  and  174,456  enlisted  men  and  civilian 
employees.  Twenty-seven  flying  fields  were  then  in 
operation,  and  9,503  training  airplanes  and  642  observa- 
tion balloons  of  various  sorts  had  been  built.  In  ad- 
dition to  this,  17,673  aeronautical  engines  for  training 
purposes  had  been  completed,  and  the  work  was  still  in 
a  state  of  rapid  development  when  it  was  stopped  by 
the  ending  of  the  war.  Considerable  money  was 
doubtless  spent  without  commensurate  material  re- 
turns, but  this  was  unavoidable  in  view  of  the  nature 
of  the  problems  that  had  to  be  handled,  and  the  pres- 
sure under  which  the  work  was  done.  The  material 
output  was  immense,  however,  and  highly  creditable 
under  the  circumstances.  In  addition,  our  knowledge 
of  aeronautics  was  vastly  increased,  aeronautical  en- 
gineers were  developed,  new  methods  of  doing  work 
were  evolved,  and  special  materials  were  devised  for 
fulfilling  special  needs.  During  this  period  the  advance 
was  so  rapid,  in  fact,  that  airplanes  sometimes  became 
obsolete  almost  before  they  could  be  completed. 


THE    FUTURE    OF    AERIAL    NAVIGATION  I  I 

THE  FUTURE  of  Aerial  Navigation:  With  the 
close  of  the  war,  it  became  necessary  to  consider 
the  future  of  aeronautics.  Many  persons  believed  that 
aircraft  would  be  found  to  be  useful  in  connection  with 
the  arts  of  peace,  and  the  success  of  aerial  navigators  in 
crossing  the  Atlantic  Ocean  certainly  took  the  question 
of  the  commercial  possibilities  of  aircraft  out  of  the  pro- 
vince of  the  dreamer,  and  forced  the  practical  business 
man  to  give  serious  consideration  to  the  subject.  Yet 
the  difficulties  to  be  overcome  are  undeniably  great,  and 
many  of  our  best  engineers  have  been  profoundly  skep- 
tical with  regard  to  every  suggestion  involving  the  use 
of  aircraft  as  a  means  of  transportation  in  time  of  peace; 
and  the  general  public,  remembering  the  numerous  acci- 
dents that  have  been  recorded  in  our  newspapers  during 
the  past  few  years,  is  strongly  disposed  to  question  the 
feasibility  of  this  mode  of  travel.  But  it  should  not  be 
forgotten  that  the  experience  during  the  war  is  not  a  fair 
index  of  what  can  be  accomplished  in  the  future, — not 
only  because  the  conditions  existing  at  that  time  were 
far  from  normal,  but  also  because  the  entire  art  was 
wholly  new,  and  involved  difficulties  that  are  only  now 
coming  to  be  fully  understood. 

/COMMERCIAL  USES  of  Aircraft:  European 
^^  countries  took  to  commercializing  aircraft  before 
the  United  States  gave  much  thought  to  the  subject, 
and  several  regular  aerial  lines  of  travel  have  already 
been  established  over  there.  In  our  own  country,  an 
aerial  mail  service  has  been  in  operation  on  certain  routes 
since  1918.  Experience  shows  this  service  to  be  prac- 
tical and  worthy  of  further  development  in  the  future. 
New  routes  are  being  established,  and  the  size  of  the 


12  INTRODUCTION 

Division  of  Aerial  Mail  Service  is  rapidly  increasing. 

Aircraft  have  also  been  employed,  for  a  considerable 
time,  by  the  Forest  Service  in  fire-patrol  duty.  The 
forests  of  California  from  San  Francisco  to  the  Mexican 
border  are  regularly  patrolled  in  this  way,  and  the 
record  established  has  been  excellent.  Observation 
balloons  are  used  as  stationary  outlooks,  and  airplanes 
are  employed  to  cover  specified  routes  daily. 

The  practicability  of  using  aircraft  for  photo- 
graphic survey  purposes,  and  to  some  extent  for  mer- 
cantile delivery  and  passenger  service,  has  been 
demonstrated  beyond  a  doubt;  and  if  commercial  avia- 
tion receives  the  necessary  financial  support,  it  will 
probably  be  only  a  short  time  before  this  means  of 
rapid  transportation  will  be  established  on  a  sound 
business  basis; — provided  a  sufficient  number  of  suitable 
landing  fields  are  established,  and  adequate  flying  laws 
and  regulations  are  enacted  and  enforced. 


I.    AIRPLANE  CONSTRUCTION 


TYPES  OF  MACHINES:  Self-propelled  aircraft 
may  be  divided  into  two  main  classes,  according 
as  they  are  (i)  lighter  than  air,  or  (2)  heavier  than  air. 
Lighter-than-air  machines  (technically  known  as  air- 
ships or  dirigibles  when  they  are  provided  with  engines 
and  propellers  so  that  they  are  capable  of  independent 
locomotion)  are  of  the  balloon  type,  and  owe  their 
lifting  power  largely  or  wholly  to  bags  filled  with  a 
gas  that  is  lighter  than  air.  Such  machines  may  be 
divided  into  (i)  rigid,  (2)  semi-rigid,  and  (3)  non-rigid 
types.  In  rigid  airships  the  gas  envelopes  are  sup- 
ported by  a  rigid  framework.  The  semi-rigid  airships 
have  a  framework  to  support  the  cars,  fins,  rudders, 
and  elevators,  and  non-rigid  types  owe  their  firmness 
entirely  to  the  pressure  in  the  gas  envelope.  The 
heavier-than-air  machine  is  of  totally  different  con- 
struction and  owes  its  lifting  power  to  the  action  of 
wings,  or  to  the  rotation  of  propellers  analogous  to  the 
screw  propellers  that  are  used  on  steamships.  If 
the  machine  were  supported  by  wings  that  flapped 
like  those  of  a  bird,  it  would  be  called  an  "ornithopter;" 


AIRPLANE    CONSTRUCTION 


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TYPES    OF    MACHINES  15 

and  if  it  were  sustained  in  the  air  by  the  direct  thrust  of 
downwardly-directed  propellers,  it  would  be  called  a 
"helicopter/'  Neither  of  these  types  has  yet  been  de- 
veloped to  a  practical  point  in  connection  with  gasless 
machines,  although  some  authorities  believe  that  the 
helicopter  will  become  practicable  in  the  near  future. 
At  the  present  time,  all  gasless  machines  of  the  "air- 
plane" type  owe  their  lifting  power  to  the  action  of 
wings  or  supporting  surfaces  which  are  fixed  and  prac- 
tically rigid,  save  for  the  fact  that  certain  relatively 
small  portions  of  them  can  be  set  or  adjusted  in  varying 
positions.  The  fixed  wings  or  "planes"  are  designed 
and  located  so  that  when  the  machine  is  in  rapid  forward 
motion,  the  air  presses  against  their  lower  surfaces  and 
also  produces  a  vacuum  over  the  top  of  the  wing, 
behind  the  leading  edge.  It  is  usually  considered  that 
about  60  per  cent,  of  the  lift  is  due  to  the  presence  of 
this  vacuum  over  the  upper  surfaces  of  the  planes. 

The  wings  were  originally  made  thin  and  nearly 
flat,  and  it  was  then  appropriate  to  call  them  "planes." 
In  recent  machines  the  wings  are  often  quite  thick,  and 
they  invariably  have  a  strongly-curved  shape  also.  It 
is  hardly  appropriate,  therefore,  to  call  them  "planes"  at 
the  present  day,  though  the  name  still  persists,  and  the 
machine  itself  will  doubtless  always  be  known  as  an 
"airplane." 

Airplanes  (to  which  our  attention  will  be  almost 
wholly  confined  in  the  remaining  part  of  this  book)  may 
be  classified  in  various  ways.  First,  they  may  be 
grouped  in  accordance  with  the  number  of  main  sup- 
porting surfaces  employed, — "monoplanes"  using  one 
pair  of  such  surfaces,  "biplanes"  using  two,  and  "multi- 
planes" using  more  than  two.  They  are  also  classified 


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AIRPLANE    CONSTRUCTION 


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TYPES    OF    MACHINES 


Photo  by  Benner. 


A  HYDROAIRPLANE. 

according  to  the  nature  of  the  service  for  which  they  are 
designed,  being  known  simply  as  "airplanes"  if  they  are 
to  operate  exclusively  from  the  land,  and  as  "seaplanes" 
if  they  are  to  be  used  for  marine  flying.  Seaplanes 
are  further  divided  into  float  seaplanes  or  "hydroair- 
planes,"  and  boat  seaplanes  or  "flying  boats."  Hydro- 
airplanes  are  similar  to  ordinary  airplanes  in  construction, 
except  that  instead  of  having  landing  carriages  and 
wheels,  each  machine  is  provided  with  a  float  or  a  set  of 
floats,  for  landing  purposes.  A  flying  boat  is  a  seaplane 
in  which  the  body  of  the  machine  acts  as  the  float. 


i8 


AIRPLANE    CONSTRUCTION 


Photo  by  Benner. 


A  FLYING  BOAT. 

Aeronautical  Engines:  Aeronautical  engines  are 
of  the  internal-combustion  type,  and  use  gasoline  as 
fuel.  They  are  all  multicylinder  in  design,  and  may  be 
either  rotative  or  fixed.  Fixed  engines  may  be  fur- 
ther subdivided,  according  to  the  arrangement  of  the 
cylinders,  into  radial,  upright,  and  V-shaped  types. 
The  number  of  engines  carried  by  an  airplane  varies, 
—some  planes  employing  but  one  each,  while  others 
have  two,  and  some  designs  call  for  three  or  more. 

In  the  matter  of  locomotion,  airplanes  are  usually 
either  "tractors"  (in  which  the  propellers  are  located 
in  front  of  the  engines  and*  pull  the  machines  through 
the.  air)  or  "pushers"  (in  which  the  propellers  are  in 
the  rear  of  the  engines,  and  force  the  airplanes  forward 
by  a  pushing  action).  In  a  pusher  plane,  the  motor  is 
usually  mounted  above  the  body;  while  in  a  tractor 
airplane  it  is  commonly  placed  at  the  nose  of  the 
fuselage.  Some  multimotored  types,  however,  com- 
bine the  pusher  and  tractor  principles  in  a  single 
machine. 

The  Structural  Parts  of  Airplanes :  Excluding 
the  power  plant,  an  airplane  can  be  divided  into  four 


THE    BODY  19 

principal  parts:  (i)  body;  (2)  wings;  (3)  tail;  and  (4) 
landing-gear.  We  proceed  to  describe  these  briefly, 
as  they  are  constituted  in  airplanes  of  the  usual  types. 
In  all-metal  planes,  which  will  be  mentioned  later,  the 
construction  of  the  various  parts  is  quite  different. 

The  Body:  The  body  of  a  tractor  plane  is 
termed  the  "fuselage,"  and  in  the  pusher-type  of 
machine  it  is  shorter  and  is  called  the  "nacelle."  The 
fuselage  or  nacelle  of  the  airplane  usually  carries  the 
dead  weight,  consisting  of  the  power  plant,  the  fuel 
and  oil  tanks,  and  the  pilot,  passengers,  and  freight. 
It  must  be  strongly  built,  and  be  constructed  so  that 
it  will  easily  and  safely  transmit  the  forward  pull  or 
thrust  from  the  propeller  to  the  rest  of  the  machine. 
This  requires  rigid  attachment  between  the  body  and 
the  wings.  In  flying  boats  the  body  construction  is 
heavier  than  in  other  airplanes,  because  in  this  type 
the  body  serves  also  as  a  large  landing  pontoon,  and 
keeps  the  plane  afloat  when  it  is  resting  on  the  surface 
of  the  water. 

The  Wings:  The  main  supporting  surfaces  of  an 
airplane  are  made  up  of  several  parts, — namely,  wing 
spars,  wing  ribs,  and  the  wing  covering; — and  wires 
and  cables  are  used  for  internal  bracing.  The  wing 
spars  run  longitudinally  along  the  wings,  receiving 
the  stress  to  which  the  wings  are  subjected,  and  trans- 
mitting it  to  the  framework  of  the  body.  There  are 
usually  two  of  these  spars  in  each  wing,  one  being  lo- 
cated near  the  leading  edge,  while  the  other  is  ordi- 
narily placed  at  about  one-fourth  of  the  length  of  the 
wing  chord  from  the  trailing  edge.  The  wing  spars  are 
usually  made  of  wood,  and  they  may  be  either  solid  or 
built  up  of  several  pieces  glued  together.  If  solid,  they 


2O  AIRPLANE    CONSTRUCTION 

are  ordinarily  made  of  ash  or  silver  spruce;  and  if 
built  up,  they  are  made  in  differing  combinations, 
varying  from  plain  strip  plywood  to  "I",  "U",  and 
box-shaped  sections. 

Wing  ribs  are  employed  to  give  the  wing  its  shape 
and  to  complete  the  framework  over  which  the  wing 
covering  is  stretched.  They  are  fitted  transversely 
between  the  wing  spars,  and  specially  designed  ones 
take  the  compression  between  these  front  and  rear 
members.  The  ribs  may  be  either  solid  or  built-up; 
and  in  airplanes  of  some  types  special  lightly-con- 
structed intermediate  ribs  are  used  for  maintaining 
the  shape  of  the  wings,  especially  in  the  nose  of  the 
wings. 

The  wing  covering,  and  sometimes  the  covering 
for  the  body  frame,  consists  of  linen  or  cotton  cloth 
drawn  tightly  over  the  framework  and  sewed  in  place. 
This  fabric  covering  must  be  perfectly  smooth  and 
taut.  When  in  position,  it  is  coated  with  a  special 
varnish-like  preparation,  technically  called  "dope," 
which  shrinks  the  cloth  and  at  the  same  time  makes  it 
waterproof.  The  warp  and  filling  threads  of  the  wing 
cloth  should  be  of  uniform  thickness  throughout  their 
length,  and  they  should  be  as  long  as  possible,  because 
knots  are  likely  to  cause  weak,  uneven  spots  in  the  cloth. 
Some  kinds  of  wing  cloth,  however,  have  extra  stout 
threads  (known  as  guide  threads)  woven  at  intervals  in 
both  the  warp  and  filling,  for  the  purpose  of  preventing 
the  extension  of  any  split  or  flaw  that  may  develop  in 
the  fabric.  Linen  is  much  stronger  than  cotton  cloth  of 
the  same  weight,  and  it  also  takes  the  dope  better.  It 
should  be  used  when  its  cost,  per  yard,  is  not  more  than 
50  per  cent,  greater  than  that  of  special  airplane  cotton. 


THE    WINGS  21 

In  the  assembled  biplane  or  multiplane,  wires, 
cables,  and  interplane  struts  are  used  to  form  a  truss- 
work  between  the  main  supporting  surfaces.  The 
interplane  struts  of  a  biplane  or  multiplane  machine 
are  all  in  compression,  and  (like  the  wing  spars)  they 
may  be  either  solid  or  built  up.  They  serve  to  keep 
the  wings  at  the  proper  distance  apart,  and  in  most 
planes  they  are  placed  vertically,  or  nearly  so,  between 
the  wings.  Struts  are  usually  made  of  spruce  or  ash,  but 
steel  struts  are  now  used  to  some  extent,  and  are  giv- 
ing excellent  results.  The  struts  are  attached  to  the 
wing  spars  by  a  metal-socket  arrangement,  and  it  is  best 
to  fasten  the  socket  to  the  spar  by  means  of  a  U-shaped 
bolt  which  passes  around  the  spar  instead  of  piercing  it. 

The  wiring  in  the  wings  of  an  airplane  is  one  of  the 
most    important    factors    in    the    construction    of   the 
machine.     For  practical  purposes,  the  wires  may  be 
divided,  according  to  their  uses,  into  four  classes,— 
flying,  landing,  drag,  and  incidence  wires. 

Flying  wires  are  used  to  support  the  weight  of  the 
fuselage  or  body,  when  the  machine  is  in  the  air.  They 
extend  from  the  bases  of  the  struts  on  the  lower  wings, 
upward  and  outward  to  the  tops  of  the  struts  on  the 
upper  wings.  The  landing  wires  pass  from  the  base  of 
each  strut  on  the  lower  wings,  upward  and  inward  to 
the  top  of  the  next  strut.  They  cross  the  flying  wires 
nearly  at  right  angles,  and  are  under  tension  only 
while  the  airplane  is  on  the  ground. 

When  a  machine  is  flying,  the  resistance  of  the  air 
has  a  tendency  to  push  the  wings  backward.  This 
drift-back  is  counteracted  by  the  drag  wires,  which,  in 
a  tractor  machine,  are  usually  attached  to  the  front  of 
the  fuselage  and  extend  back  to  the  lower  ends  of  the 


22 


AIRPLANE    CONSTRUCTION 


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THE    WINGS  23 

struts.    In  a  pusher-type  machine  the  wires  are  usually 
attached  to  the  front  of  the  outrigging,  or  to  the  nacelle, 
'and  extend  to  the  outer  struts. 

Incidence  wires  are  used  to  adjust  and  maintain 
the  angle  of  incidence.  They  take  the  form  of  cross- 
bracing  between  each  front  strut  and  the  corresponding 
rear  strut.  Incidence  wires  are  sometimes  called  "stag- 
ger-wires," because  they  are  also  used  in  regulating  the 
stagger  of  the  wings. 

As  a  rule,  all  wires  are  adjustable  by  means  of  turn- 
buckles.  This  arrangement  makes  it  possible  to  slacken 
or  tighten  the  wires  when  necessary.  The  threads  on 
the  turnbuckles  should  be  strong  enough  to  insure 
safety,  and  a  locking  device  of  some  kind  should  be 
used  on  them,  to  avoid  any  possible  chance  of  the  ad- 
justment becoming  changed  accidentally,  or  in  conse- 
quence of  the  vibration  of  the  machine. 

Modern  airplanes  have  "ailerons,"  or  hinged  flaps, 
attached  to  the  rear  edges  of  the  wings,  at  or  near  their 
outer  ends.  These  are  used  to  stabilize  the  machine 
laterally.  As  long  as  the  ailerons  remain  in  a  neutral 
position  they  do  not  disturb  the  equilibrium;  but  as 
soon  as  the  ailerons  on  either  side  are  raised  or  lowered, 
the  machine  tends  to  tilt  sidewise; — that  is,  to  rotate 
one  way  or  the  other  about  its  fore-and-aft  axis.  They 
permit  the  pilot  to  right  his  machine  in  case  it  should 
be  tilted  by  a  gust  of  wind,  and  to  tilt  or  "bank"  the 
machine  when  a  turn  is  made.  Ailerons  that  are  long 
and  narrow  are  said  to  be  more  effective  and  more 
easily  operated  than  short  ones  having  the  same  area. 
The  aileron  surface  should  be  equal  to  about  10  per 
cent,  of  the  wing  area. 

The  Tail:     There  are  two  distinct  types  of  tails, 


24  AIRPLANE    CONSTRUCTION 

—the  lifting  and  non-lifting.  The  lifting  tail  may  have 
a  surface  cambered  similarly  to  the  main  support- 
ing surface,  but  in  most  cases  the  angle  of  incidence  at 
which  the^  tail  planes  are  set  causes  a  slight  lift.  A 
lifting  itail  supports  only  its  own  weight  however,  and 
contributes  nothing  to  the  support  of  other  parts  of 
the  machine.  The  non-lifting  tail  has  a  surface  either 
flat  or  possessing  a  slightly  convex  camber  on  both  sides. 
It  is  designed  to  act  as  a  horizontal  fin  or  stabilizer,  and 
is  set  so  as  not  to  have  a  lifting  effect,  but  to  give 
steadiness  in  a  fore-and-aft  direction,  and  prevent 
motions  of  the  airplane  analogous  to  the  "pitching" 
of  a  ship. 

The  trailing  edge  of  the  horizontal  stabilizer  is 
usually  constructed  of  metal  tubing  to  form  the  rear 
spar,  and  the  elevator  planes  are  hinged  to  this  spar. 
The  stabilizers  and  elevators  should  have  a  combined 
area  equal  to  about  15  per  cent,  of  the  total  wing  sur- 
face. Elevators  are  said  to  be  more  effective  if  built 
long  and  narrow. 

A  vertical  stabilizer  or  fin  is  placed  along  the 
upper  center-line  of  the  tail,  and  extends  back  to  the 
tail  post  of  the  body.  The  rudder  is  attached  to  the 
trailing  edge  of  this  fin,  and  to  the  tail-post,  by  hinges 
and  pins,  in  a  manner  similar  to  that  employed  in 
attaching  a  rudder  to  a  ship.  The  rudders  and  fins 
should  have  a  combined  area  equal  to  about  one-half 
that  of  the  stabilizers,  and  should  be  located  so  that 
they  will  not  be  blanketed  by  the  airplane  body. 

The  Landing  Gear:  The  chassis  of  an  air 
plane  is  usually  a  V-shaped  structure,  strongly  cross- 
braced  and  fitted  to  the  lower  side  of  the  fuselage. 
Similar  cross-braced  construction  is  employed  on  sea- 


MATERIALS    USED  25 

planes.  The  landing  gear  or  undercarriage  has  two 
distinct  forces  to  resist:  (i)  the  vertical  shock  ex- 
perienced upon  landing,  and  (2)  the  horizontal  force 
that  tends  to  sweep  the  landing  gear  backward  when 
the  airplane  is  running  along  the  ground.  The  former 
of  these  forces  is  greatest  when  a  machine  is  "pan- 
caked/' and  the  latter  reaches  its  maximum  when  a  fast 
landing  is  made  on  soft  or  rough  ground.  A  large  factor 
in  the  landing  stress  of  an  airplane  is  what  is  commonly 
known  as  "side-swipe".  This  is  partially  counteracted 
by  means  of  cross  bracing  in  the  landing  gear. 

The  vertical  shock  is  relieved  to  some  extent  by  the 
use  of  rubber  shock-absorbers,  and  the  horizontal 
resistance  is  reduced,  on  airplanes,  by  means  of  wheels, 
and  on  seaplanes  by  the  use  of  long,  narrow  pontoons. 

Structural  Materials  Used:  The  choosing  of 
material  for  aircraft  construction  is  a  study  in  itself. 
It  is  necessary  to  insure  great  strength  and  absolute 
reliability,  without  sacrificing  lightness.  The  problem 
has  been  solved  sufficiently  to  permit  successful  flying, 
but  further  study  and  research  will  doubtless  result 
in  marked  improvement  in  the  selection  of  material. 

Wood  is  largely  used  in  the  construction  of  the 
framework.  The  chassis  struts,  skids,  longerons,  and 
engine-bearers  are  usually  made  of  ash.  This  is  a 
straight-grained,  tough  wood,  but  it  is  rather  heavy. 
Spruce  is  extensively  used  for  the  main  spars,  wing 
spars,  and  struts.  It  is  not  so  strong  as  ash,  but 
it  is  considerably  lighter  and  is  quite  dependable,  and 
hence  it  is  always  used  when  it  can  be  obtained  in 
clear,  sound,  straight-grained  lengths.  Members  are 
frequently  built  up  of  sections  of  ash  and  spruce,  glued 
together.  Ribs  are  usually  made  of  white  pine.  Hick- 


26  AIRPLANE    CONSTRUCTION 

ory  is  used  for  landing-gear  struts,  especially  in  the 
construction  of  heavy  machines.  Canadian  elm  is  very 
tough  and  is  sometimes  used  instead  of  ash  for  engine 
bearers  and  longerons.  It  is  easily  twisted  and 
warped,  however,  and  for  that  reason  it  is  not  wholly 
ideal.  Basswood  is  used  in  the  webs  of  ribs;  and  wal- 
nut, mahogany,  and  ash  are  used  in  propeller  con- 
struction. 

Aluminum  is  employed  in  constructing  cowl  sup- 
ports, wind-screen  frames,  and  control  wheels.  It  is  not 
particularly  desirable  in  connection  with  seaplanes  or 
flying  boats,  because  it  corrodes  easily  in  the  presence 
of  water,  and  when  it  is  used  it  must  be  constantly 
watched  and  frequently  cleaned.  Manganese  bronze 
is  quite  tough,  and  on  account  of  its  resistance  to  cor- 
rosion it  is  used  largely  in  airplanes  operating  from  the 
water.  It  is  also  employed  in  making  wood  screws,  and 
for  bearings  for  rotating  parts.  Phosphor-bronze  has 
properties  resembling  those  of  manganese  bronze,  and 
it  is  used  for  similar  purposes. 

Steel  is  used  for  sockets  and  control  leads,  and  for 
wire  and  wire  attachments; — in  fact,  for  all  kinds  of 
airplane  fittings.  Some  builders  have  employed  steel 
for  the  entire  framework,  but  such  construction  is 
heavy  and  difficult  to  repair.  Steel  tubes  may  be 
used  as  struts,  and  in  some  cases  a  stream-line  cross- 
section  is  given  to  these  tubes  by  the  application  of 
sheet  metal  or  balsa  wood,  externally. 

Duralumin — a  special  alloy  of  aluminum,  copper, 
and  magnesium, — has  recently  been  used  in  aircraft 
construction  for  all  the  purposes  for  which  wood  has 
hitherto  been  employed,  except  for  making  propellers. 
This  alloy  is  tough,  strong,  and  light  in  weight,  and  is 


MATERIALS    USED 

Courtesy  JL  Aircraft  Corporation. 


AN  ALL-METAL  MONOPLANE. 

likely  to  play  an  important  part  in  the  aircraft  of  the 
future.  An  incidental  but  important  advantage  as- 
sociated with  the  use  of  duralumin  in  the  construction 
of  all-metal  machines  consists  in  the  fact  that  when  an 
accident  occurs  the  metallic  construction-members 
bend  and  crumple  up,  thereby  absorbing  part  of  the 
energy  of  motion  of  the  machine  and  lessening  the 
violence  of  the  shock.  Wood,  under  similar  stress, 
splits  and  snaps,  and  the  broken  ends  often  cause  serious 
injuries. 

To  obtain  the  best  results  with  duralumin,  the 
alloy  must  be  heat-treated  before  working,  by  subject- 
ing it  to  a  temperature  of  from  350°  to  380°  C.  and 
then  quenching  in  oil  or  hot  water.  The  metal  is 
thereby  rendered  plastic,  so  that  it  can  be  easily  forged, 
stamped,  drawn,  or  rolled.  After  working,  a  final  heat 
treatment  is  necessary  in  order  to  give  the  alloy  its 


.28 


AIRPLANE    CONSTRUCTION 


maximum  hardness  and  strength.  For  this  purpose  it 
is  heated  to  500°  C.  or  520°  C.,  quenched  in  oil  or  hot 
water,  and  then  allowed  to  stand  for  about  a  week, — at 
the  end  of  which  time  it  will  have  become  permanently 
hard  and  durable.  The  heating  is  a  delicate  operation 
and  is  usually  performed  by  the  aid  of  a  salt  bath 
composed  of  equal  parts  of  nitrate  of  sodium  and  nitrate 
of  potassium, — the  mixed  nitrates  melting  at  a  tem- 
perature that  is  materially  lower  than  the  melting 
point  of  either  one  when  used  alone.  Accurate  ther- 
mometers or  pyrometers  must  be  used  in  this  work,  and 
the  temperature  of  the  bath  must  be  closely  watched 
and  carefully  regulated;  because  if  the  metal  is  heated 
above  550°  C.  it  becomes  permanently  hard  and  brittle, 
and  its  strength  is  also  materially  reduced.  If  heated 

Courtesy  Air  Service,  U.  S.  A. 


AN  ALL-METAL  BIPLANE. 


CONTROL  29 

even  a  few  degrees  above  520°  C.  the  alloy  loses  some 
of  its  desirable  qualities.  Equal  care  is  required  in  the 
preliminary  heat  treatment  used  in  preparing  the 
metal  for  working,  because  if  a  temperature  of  400°  C. 
is  reached  during  this  annealing  process,  the  metal 
becomes  hard  and  difficult  to  work. 

Linen  and  Egyptian  cotton  cloth  are  the  principal 
fabrics  used  for  covering  the  framework  of  the  wings, 
and  the  fuselage  or  nacelle.  Recently,  thin  sheets  of 
corrugated  duralumin  have  been  used  experimentally 
in  place  of  fabric  for  wing  and  body  coverings,  and  it 
is  said  that  the  metal  has  served  this  purpose  admirably. 

Control:  There  are  three  points  of  control  in  the 
standard  type  of  airplane, — namely,  (i)  the  ailerons 
located  along  the  trailing  edges  of  the  wings  and  near 
their  outer  ends,  (2)  the  elevators  at  the  rear  of  the 
fuselage,  and  (3)  the  rudder  (or  rudders,  when  there  are 
more  than  one)  located  in  the  rear  of  the  body.  These 
parts  are  operated  from  the  pilot's  seat  by  means  of 
levers  and  wire  cables. 

The  rudder  is  normally  operated  by  means  of  a 
foot-bar,  and  is  used  for  the  same  purpose  as  the  rudder 
of  a  boat.  A  lever,  called  a  control-stick  or  "joy-stick," 
is  commonly  used  for  controlling  the  ailerons  and  the 
elevators.  In  some  cases,  however,  a  wheel  is  employed 
instead  of  a  control-stick.  A  fore-and-aft  movement  of 
the  wheel  or  stick  controls  the  elevators,  and  the  ailerons 
are  operated  by  rotating  the  wheel  or  by  moving  the 
stick  sidewise.  The  elevators  control  the  vertical 
movements  of  the  airplane,  while  the  ailerons,  which 
control  the  movements  that  correspond  to  the  "rolling" 
of  a  ship,  are  used  principally  in  banking  for  turns.  The 
ailerons  are  usually  of  the  double-acting  type,  in  which 


30  AIRPLANE    CONSTRUCTION 

compensating  wires  are  used.  When  the  aileron  on  one 
side  is  deflected  upward  by  means  of  the  control  lever, 
the  opposite  aileron  is  simultaneously  lowered  by  means 
of  the  compensating  wires.  In  other  words,  the  construc- 
tion is  such  that  the  elevation  of  one  of  the  ailerons  is  nec- 
essarily attended  by  the  depression  of  the  opposite  one. 

The  method  of  running  the  control  cables,  as  well 
as  the  construction  of  them,  is  extremely  important. 
They  should  always  run  through  well  lubricated  leads, 
and  every  precaution  should  be  taken  against  clogging 
or  jamming.  Sharp  angles  in  the  cables  should  be 
avoided  by  the  use  of  chains  or  bell-cranks  or  other 
similar  arrangements.  All  control  cables  should  be 
flexible,  and  it  is  advisable  to  have  them  in  duplicate, 
wherever  possible.  The  main  point  is  to  insure  absolute 
freedom  and  certainty  of  movement,  because  the 
safety  of  the  airplane  depends  at  all  times  upon  the 
positive  operation  of  its  controls. 

Certain  special  stabilizing  devices,  embodying  the 
principle  of  the  gyroscope,  are  used  in  some  machines. 
To  what  extent  they  will  be  employed  in  commercial 
aviation  (if  at  all)  is  thus  far  undetermined.  Even  the 
value  of  them  is  not  yet  universally  conceded.  Stabil- 
izers of  some  forms  can  be  set  or  fixed  in  position  so 
that  the  airplanes  in  which  they  are  installed  will  run 
in  a  predetermined  course,  subject  only  to  wind-drift- 
ing, as  long  as  the  motor  operates.  Aviators  have 
been  known  to  start  their  stabilizers  and  then  sit  in 
their  seats  writing  letters,  paying  no  attention  to  their 
controls.  This  is  an  exceedingly  unwise  practice, 
because  it  is  always  dangerous  to  place  too  implicit 
a  dependence  upon  automatic  devices  of  any  kind, 
especially  when  failure  would  be  followed  by  disas- 


PLAN    AND    PERFORMANCE  3! 

trous  consequences.  The  aviator  should  give  his 
personal  and  immediate  attention  to  the  control  of  his 
machine  at  all  times,  and  should  never  rely  upon 
automatic  apparatus.  Such  apparatus  is  useful  in  so  far 
as  it  assists  the  aviator,  but  he  must  be  watchful  of  his 
machine  at  every  moment  that  he  is  in  the  air. 

Plan  and  Performance:  Airplanes  of  nu- 
merous makes  and  models  are  now  produced  com- 
mercially, and  each  of  them  has  its  own  good  points. 
As  in  selecting  an  automobile,  the  use  to  which  the 
machine  is  to  be  put  should  be  the  chief  factor  in 
making  a  choice.  There  are  certain  points  in  airplane 
construction,  however,  that  determine  the  usefulness 
of  the  craft  for  any  purpose,  and  these  should  receive 
serious  consideration. 

In  the  first  place,  the  airplane  should  be  of  a  clean- 
cut  design,  and  stream-lined,  and  the  gaps  between  the 
control  surfaces  and  the  main  sections  should  be  small. 

The  stability  required  in  a  machine  will  depend 
largely  upon  the  purpose  for  which  the  airplane  is  to  be 
used.  A  certain  amount  of  stability  is  essential  to  safety, 
but  in  low-powered  aircraft  excessive  stability  causes 
the  machine  to  be  subject  to  violent  reactions  in  a  gusty 
wind,  and  makes  it  hard  to  handle.  When  such  planes 
have  too  much  stability,  they  are  extremely  safe  but 
very  uncomfortable  to  ride  in.  Lateral  stability  is 
secured  by  a  combination  of  rear  fin  area  and  wing 
dihedral;  and  longitudinal  stability  depends  upon  the 
location  of  the  center  of  gravity  relatively  to  the  wings. 
The  airplane  will  be  unstable  unless  the  horizontal  tail 
surfaces  are  set  at  a  negative  angle  with  respect  to  the 
wings; — that  is,  unless  the  entering  edges  of  the  horizon- 
tal stabilizers  are  slightly  lower  than  the  trailing  edges. 


32  AIRPLANE    CONSTRUCTION 

The  ease  with  which  an  airplane  can  get  off  the 
ground  depends  primarily  upon  the  design  of  the  wings. 
A  low  load  per  horse-power  will  enable  a  plane  to  lift 
quickly,  and  ability  to  do  this  is  also  obtained  if  the 
load  per  square  foot  of  wing  surface  is  low.  A  propeller 
of  small  diameter  is  desirable  in  obtaining  the  maximum 
number  of  revolutions  per  minute  from  the  motor  while 
the  plane  is  still  on  the  ground,  but  is  not  desirable  when 
the  plane  is  in  the  air.  A  large  propeller  is  then  pre- 
ferable, in  order  to  obtain  a  maximum  amount  of  power. 
Increased  ease  of  "get-away"  involves  a  corresponding 
sacrifice  in  lifting  power  or  useful  load. 

Speed  in  the  air,  and  climbing  ability,  are  not 
paramount  considerations  in  commercial  planes,  yet 
these  characteristics  are  sometimes  highly  desirable 
when  it  becomes  necessary  to  avoid  trees,  houses, 
smokestacks,  and  other  obstacles  near  a  flying  field. 
If  an  airplane  travels  at  its  maximum  speed  a  consider- 
able part  of  the  time,  the  engine  is  subjected  to  an  enor- 
mous amount  of  wear  and  tear  and  it  will  not  stand  up 
long  under  the  strain.  A  plane  should  have  a  flying 
speed  compatible  with  the  work  it  is  engaged  in,  and 
still  have  some  speed  in  reserve  for  use  in  an  emergency. 
A  high  ceiling  is  desirable  in  a  mountainous  country, 
where  flying  at  considerable  altitudes  is  necessary  in 
order  to  clear  high  peaks. 

An  airplane  having  deeply  cambered  wings  is  likely 
to  possess  great  lifting  power.  Commercial  planes 
should  have  wings  that  are  moderately  cambered, 
—a  compromise  between  those  of  a  speed  plane  and 
those  of  the  extremely  slow  type.  Low  flying  speed 
enables  a  plane  to  land  with  less  shock,  and  also  to  come 
to  rest  soon  after  striking  the  ground.  This  is  import- 


PLAN    AND    PERFORMANCE 


33 


ant  in  connection  with  planes  that  may  have  to  land  in 
restricted  areas,  but  on  the  other  hand  too  low  a  land- 
ing speed  is  undesirable  on  account  of  the  reactions 
to  which  the  plane  is  subjected  in  gusty  winds.  It  is 
possible  to  reduce  the  landing  speed  by  flattening  out 
the  dive,  and  landing  with  the  speed  slightly  below  the 
theoretical  value. 

The  head  resistance  of  the  airplane  and  the  drag 
of  the  tail  skid  reduce  the  distance  a  machine  must  taxi 
after  landing.  A  large  angle  of  incidence  in  the  wings 
creates  a  large  amount  of  head  resistance.  With  the 
tail  skid  on  the  ground,  a  sixteen-degree  angle  of  inci- 
dence between  the  wing  surfaces  and  the  line  of  flight 
is  considered  to  be  about  the  minimum  value  for  general 
work.  The  center  of  gravity  of  the  machine  should  be 
at  least  twelve  inches  back  of  the  wheel  axis  of  the  land- 
ing gear,  to  resist  the  tendency  of  the  machine  to 

Courtesy  Curtiss  Aeroplane  and  Motors  Corporation. 


SAND-TESTING  AN  AIRPLANE  WING. 


34  AIRPLANE    CONSTRUCTION 

"nose  over."  This  position  of  the  center  of  gravity 
also  insures  a  reasonable  amount  of  drag  on  the  tail 
skid. 

The  factor  of  safety  should  be  at  least  six  in  the 
construction-members  of  large,  stable  planes,  but  in 
smaller  types  that  are  subject  to  manoeuvers  it  should 
be  increased  to  at  least  twelve  or  fourteen.  The  materi- 
als used  in  all  the  members  of  an  airplane  should  be 
thoroughly  tested,  to  be  sure  they  are  sufficiently 
strong. 

In  the  power  plant,  high-compression  engines  are 
not  considered  as  reliable  as  low-compression  ones, 
especially  when  high  compression  is  coupled  with  high 
piston  speed.  Most  airplane  engines  are  equipped  with 
two  sets  of  spark  plugs,  and  it  is  still  better  to  have  two 
or  more  entirely  separate  ignition  systems.  Ignition 
trouble  frequently  causes  engine  failure,  but  if  two  or 
more  separate  ignition  units  are  used,  the  failure  of 
one  of  them  will  not  force  the  pilot  to  stop  flying.  He 
can  continue  to  operate  on  his  duplicate  or  reserve  unit 
until  he  can  get  to  a  suitable  place  to  land  and  make 
repairs. 

Multiple  engines  are  desirable  for  the  same  reason; 
for  if  one  of  them  fails,  the  pilot  can  usually  continue 
flying  under  partial  power  long  enough  to  reach  a 
suitable  landing  place.  Multi-motored  airplanes  require 
extra  large  and  extra  strong  rudders,  to  compensate  for 
the  one-sided  pull  that  is  exerted  if  some  of  the  engines 
are  not  working  properly.  Without  reliable  rudder 
control,  the  machine  is  likely  to  side-slip  under  these 
conditions. 

It  is  important  to  have  the  gasoline  feed-pipe 
arranged  so  that  there  will  be  no  chance  of  accidental 


PLAN  AND    PERFORMANCE  35 

ignition  of  the  fuel  supply.  The  feed-pipe  is  frequently 
installed  in  such  a  way  that  it  passes  close  to  the  ignition 
apparatus,  where  a  leak  would  surely  produce  a  fire. 
This  is  a  serious  error  in  design.  Gasoline  feed-pipes 
should  be  kept  well  away  from  all  sparking  devices, 
fuse  blocks,  and  switches,  and  from  all  the  highly 
heated  parts  of  the  motors.  They  should  also  be  made 
of  soft  copper  or  other  satisfactorily  flexible  tubing, 
so  that  the  chance  of  breakage  will  be  reduced  to  the 
lowest  practicable  point. 


II.     THE   OPERATION   OF 
AIRPLANES 


TNTRODUCTORY:  The  safe  operation  of  an  air- 
A  plane  depends  largely  upon  two  factors:  (i)  the 
efficiency  and  fitness  of  the  pilot,  and  (2)  the  phys- 
ical condition  of  the  machine  he  is  operating.  To 
make  sure  that  the  airplane  is  in  proper  condition  for 
flying,  it  is  necessary  for  the  pilot  to  inspect  his  machine 
thoroughly  before  leaving  the  ground.  This  inspection 
should  be  carried  out  in  accordance  with  a  definite 
plan  or  system,  in  order  to  be  sure  that  none  of  the 
vital  parts  of  the  machine  are  overlooked. 

Tuning-up:  In  making  an  inspection,  it  is 
good  practice  for  the  pilot  to  take  a  position  on  the 
right  or  left  side  of  the  fuselage,  and  then  make  a 
complete  circuit  of  the  machine,  either  to  the  right  or 
to  the  left,  carefully  looking  over  and  testing  the  various 
parts  as  he  goes  along.  The  fabric  or  wing  coverings, 
cables,  bracing  wires,  interplane  struts,  landing  gear, 
tail  skid,  control  surfaces,  and  control  cables  should 
receive  special  attention. 

The  fabric  should  be  tight  and  free  from  rips  and 
tears,  and  all  small  holes  should  be  patched  and  well 


TUNJNG-UP  37 

protected  by  dope  or  varnish.  Loose  fabric  increases 
what  is  known  as  "skin  friction/'  and  retards  speed 
in  flying.  Exposed  fabric  deteriorates  with  extreme 
rapidity,  and  airplanes  should  therefore  be  protected 
from  the  weather  when  not  in  use.  Oil  destroys  the 
fabric  varnish  and  for  that  reason  any  grease  or  oil 
that  may  be  found  upon  the  wings  should  be  carefully 
and  thoroughly  removed. 

The  cables  and  bracing  wires  should  receive  a 
light  coating  of  grease  or  oil  to  protect  them  from  rust. 
Cables  that  show  frayed  or  broken  strands  should  not 
be  repaired,  but  should  be  immediately  replaced  by 
new  cables.  The  flying  and  landing  wires  should  be 
under  sufficient  tension  to  keep  the  framework  rigid, 
but  it  should  be  remembered  that  too  much  tension 
subjects  the  parts  of  the  framework  to  needless  strain, 
and  thereby  lowers  the  factor  of  safety  that  has  been 
provided  for  the  purpose  of  taking  care  of  the  unforeseen 
stresses  to  which  the  machine  may  be  subjected  in  its 
regular  operation.  Examine  all  turnbuckles  for  loose 
or  missing  safety  or  locking  wires.  If  these  locking 
wires  are  absent  or  loose,  the  barrels  of  the  turnbuckles 
may  turn  and  release  the  tension  on  the  bracing  wires. 
See  if  any  of  the  cotter  pins  or  nuts  have  been  lost, 
and  replace  those  that  are  missing. 

The  interplane  struts  should  be  examined  for 
splits,  cracks,  and  warping.  Warped  struts  are  likely 
to  break  down  under  the  pressure  to  which  they  are 
subject.  The  socket  arrangements  by  which  the  struts 
are  fastened  are  usually  connected  to  the  wing  fixtures 
by  pins  or  bolts,  and  these  pins  or  bolts  should  be  locked 
in  position  by  means  of  split  pins. 

Wing  skids   are   not   always   provided,   but   their 


38  OPERATION    OF    AIRPLANES 

use  is  highly  recommended.  They  are  not  needed  in 
a  perfect  landing,  but  on  rough  ground,  or  in  landing 
with  one  wing  low,  they  are  of  great  advantage  in 
avoiding  the  possibility  of  a  serious  crash.  They  are 
specially  valuable  if  the  airplane  has  ailerons  attached 
to  the  lower  wing. 

The  landing  gear  struts  should  be  well  bedded  in 
their  sockets,  because  otherwise  the  shock  of  a  rough 
landing  will  drive  them  in  further,  and  in  this  way 
loosen  the  tension  on  the  cross-bracing  wires.  This 
would  throw  the  whole  undercarriage  out  of  alinement 
and  might  greatly  weaken  it.  It  would  also  prevent 
the  machine  from  taxying  straight.  The  shock-ab- 
sorbers should  be  examined  closely, — particularly  if 
they  are  composed  of  rubber,  because  this  material 
deteriorates  even  from  mere  exposure  to  sunlight,  and 
is  quickly  destroyed  by  the  action  of  lubricating  oil 
or  grease.  Make  sure,  also,  that  the  wheels  are  securely 
fastened  to  the  chassis  and  that  they  are  properly 
oiled.  They  should  revolve  freely,  and  the  tires  should 
be  properly  inflated. 

The  tail  skid  and  post  are  frequently  overlooked 
during  an  inspection,  but  they  are  important  parts  of 
the  airplane  and  should  receive  proper  consideration. 
They  are  probably  broken  and  repaired  more  frequently 
than  any  other  airplane  parts.  If  the  shock-absorber 
portion  should  become  loose  or  permanently  stretched, 
the  shock  of  landing  (which  is  relieved  by  the  tail  skid) 
would  be  received  by  the  fuselage,  and  the  whole  frame- 
work would  be  likely  to  be  severely  strained. 

The  control  surfaces  should  be  examined  to  see 
that  they  operate  easily  and  positively.  The  horns 
should  be  tight,  and  the  hinges  should  be  secure  and  in 


TUNING-UP  39 

perfect  condition,  and  the  hinge-pins  should  be  in  place 
and  properly  locked.  The  cable  attachments  should 
also  be  carefully  examined.  The  cables  should  be 
followed  throughout  their  entire  length,  and  any  defec- 
tive places  should  be  noted  and  remedied.  Lubricating 
oil  should  be  applied  freely  wherever  a  lead  passes 
through  a  pulley  or  sheave,  and  special  care  should  be 
taken  to  see  that  the  cable  is  not  frayed  at  such  points. 
Unnecessary  slack  in  the  cable  leads  will  cause  the 
control  surfaces  to  act  sluggishly,  and  will  make  it 
difficult  to  handle  the  machine  effectively  in  an  emer- 
gency. 

The  general  examination  of  the  airplane  being  com- 
pleted, attention  is  next  directed  to  the  engine,  and  to  the 
fuel  and  water  supplies,  the  instruments,  and  the  person- 
al equipment.  The  supplies  of  fuel  and  water  are  nor- 
mally taken  care  of  by  an  attendant  assigned  to  that 
duty,  but  it  is  well  to  check  up  his  work,  especially  if  a 
cross-country  flight  is  contemplated.  Personal  in- 
spection of  the  engine  is  not  absolutely  necessary, 
because  defects  in  this  part  of  the  mechanism  will 
probably  betray  themselves  during  the  warming-up 
process.  It  is  important,  however,  to  look  it  over  in  a 
general  way,  and  the  aviator  should  at  all  events  make 
sure  that  there  are  no  leaks  in  the  gasoline  tank  or  the 
feed  pipes,  or  see  that  any  such  leaks  that  exist  are 
immediately  repaired. 

On  entering  the  airplane,  the  safety  belt  should  be 
adjusted  promptly.  Examine  the  instruments  and 
make  sure  that  the  altimeter  is  set  at  zero.  If  the  fuel 
is  supplied  to  the  engine  under  pressure,  pump  up  the 
necessary  pressure  by  means  of  the  hand  pump  provided. 
Test  the  controls  to  see  that  they  operate  freely  and 


4O  OPERATION    OF    AIRPLANES 

effectively.  The  spark  control,  and  the  switches, 
gasoline  shut-off,  oil-pressure  gage,  air  release,  and 
other  controls  and  appliances  should  be  tried,  and  ad- 
justed so  that  they  work  properly. 

When  ready  to  start  the  engine,  see  that  the  blocks 
are  secure  in  front  of  the  chassis  wheels, — and  be  spe- 
cially sure  that  the  throttle  is  only  partly  open,  be- 
cause many  serious  accidents  have  occurred  in  conse- 
quence of  turning  over  the  engine  while  the  throttle 
was  open  too  wide.  Orders  given  to  the  attendant 
should  be  clear  and  distinct,  and  they  should  be  repeat- 
ed by  him  before  being  carried  out.  It  is  advisable  to 
pull  the  control  stick  well  back,  in  order  to  prevent  the 
tail  from  lifting  and  to  avoid  turning  a  somersault  over 
the  blocks. 

The  use  of  mechanical  starters  cannot  be  too 
strongly  recommended,  because  they  largely  elimi- 
nate the  accidents  associated  with  starting.  Various 
kinds  of  starters  are  available,  ranging  from  small 
compressed-air  devices  to  large  separate  cranking 
machines  mounted  on  light  motor-trucks.  On  com- 
mercial routes  it  has  been  suggested  that  the  planes  be 
equipped  with  starting  motors,  and  that  the  batteries 
needed  to  operate  these  motors  be  mounted  on  small 
trucks  that  can  be  wheeled  around  to  the  different 
planes  on  the  field  as  needed.  This  plan  would  provide 
electric  starting  apparatus  and  yet  it  does  not  require 
each  plane  to  carry  a  storage  battery. 

Never  run  the  speed  of  the  motor  up  beyond  600 
revolutions  per  minute,  until  the  temperature  of  the 
engine  is  at  least  60°  Fahr.  Undue  speed  when  starting 
strains  the  motor  and  causes  it  to  heat  up  too  quickly, 
and  quick  heating  is  likely  to  warp  the  valves  and 


CLOTHING    AND    EQUIPMENT  4! 

prevent  them  from  seating  properly.  After  the  motor 
has  attained  a  temperature  of  60°  Fahr.  it  may  be  run 
faster,  and  the  throttle  may  be  slowly  opened  to  make  a 
full-speed  test  for  vibration,  and  to  see  that  the  engine 
works  properly.  The  throttle  should  be  opened  up 
gradually  until  it  is  wide  open,  and  full  speed  should 
not  be  maintained  for  more  than  a  few  seconds.  Then 
slow  the  engine  down  to  about  three-quarters  of  its 
maximum  rate,  and  run  it  at  that  speed  until  you  are 
thoroughly  satisfied  that  everything  is  working  properly, 
and  you  are  ready  to  take  the  air. 

If  the  engine  misses  fire  while  taxying  to  the 
"take-off"  or  if  it  does  not  work  properly  in  any  other 
respect,  do  not  "take  off\  but  return  to  the  starting 
point  and  test  out  the  engine  and  make  the  necessary 
adjustments  until  it  operates  satisfactorily.  An  engine 
that  does  not  work  smoothly  is  likely  to  cause  the 
machine  to  lose  speed  in  taking  off,  and  a  sudden  fall 
may  result. 

Standard  Clothing  and  Equipment:  The 
selection  of  clothing  and  other  personal  equipment 
is  largely  a  matter  of  taste  and  circumstances.  Pro- 
vision should  be  made  for  cold  weather,  especially 
if  an  extended  flight  is  contemplated.  The  regulation 
leather  coat  is  desirable  because  it  keeps  out  wind  and 
moisture,  and  at  the  same  time  retains  the  heat  of  the 
body.  The  one-piece  flying  suit  and  sheep-lined  fly- 
ing moccasins  are  recommended. 

Nearly  all  flyers  wear  goggles,  because  they  afford 
comfort  and  protection  for  the  eyes.  If  goggles  are 
not  worn,  flying  is  likely  to  produce  spasm  in  the  eyes, 
and  it  sometimes  brings  on  a  special  form  of  conjunc- 
tivitis. The  lenses  of  the  goggles  should  be  constructed 


42  OPERATION    OF    AIRPLANES 

so  that  the  eyes  will  not  be  damaged  by  splinters  of 
glass  in  case  of  an  accident.  One  well-known  method  of 
achieving  this  end  is  to  make  each  lens  of  two  thin 
pieces  of  glass,  with  a  film  of  transparent  celluloid 
cemented  between  them.  In  case  of  fracture  the  broken 
pieces  then  adhere  to  the  central  layer  of  celluloid, 
and  the  danger  to  the  eyes  is  thereby  materially 
reduced.  The  nose-piece  of  the  goggles  should  be  made 
of  some  soft,  non-metallic  substance,  that  will  not 
injure  the  nose.  Safety  helmets  are  valuable  for 
protecting  the  head  from  injury  in  a  crash.  They 
should  be  light  in  weight  and  should  fit  properly,  so 
they  will  not  be  dislodged  easily. 


III.    AIRPLANE  ACCIDENTS 


/GENERAL  CAUSES  OF  ACCIDENTS:  An  air- 
VJ  plane  accident  is  hardly  ever  due  to  a  single  cause. 
Usually  several  factors  are  involved,  among  which  may 
be  mentioned  structural  defects,  engine  trouble,  error 
in  judgment,  physical  illness,  fatigue,  and  "loss  of 
head."  If  only  one  of  these  factors  influenced  the 
situation,  an  airplane  could  usually  be  landed  safely; 
but  if  (for  example)  the  engine  stops,  the  pilot  is  likely 
to  "lose  his  head"  and  do  something  he  should  not  do, 
or,  if  he  is  fatigued,  his  condition  will  probably  affect 
the  soundness  of  his  judgment  and  the  result  may  be 
quite  serious. 

A  survey  of  the  accidents  that  occurred  during  a 
period  of  six  months  at  one  flying  field,  shows  that  in 
9,000  flights  there  were  fifty-eight  crashes,  in  which  six- 
teen men  were  seriously  injured.  Four  of  these 
accidents  were  considered  unavoidable,  and  only  one 
was  caused  by  the  failure  of  the  airplane.  The  re- 
mainder were  due  to  the  ineptitude  of  the  pilots,— 
forty-two  being  caused  by  lack  of  judgment,  seven  by 
loss  of  head,  and  four  by  fatigue. 


44 


AIRPLANE    ACCIDENTS 


I 

H  I 


2    £ 


ERRORS    OF    THE    PILOT  45 

In  their  relative  proportions,  these  figures  are  fairly 
representative  of  the  experience  on  most  flying  fields, 
both  in  Europe  and  in  the  United  States.  They  serve 
admirably  to  show  the  importance  of  having  the  very 
best  type  of  pilot  obtainable; — one  who  is  physically, 
morally,  and  mentally  fit,  and  competent  in  every  way. 

Errors  of  the  Pilot:  An  error  in  judgment  is 
perhaps  the  most  common  cause  of  airplane  accidents. 
A  pilot  frequently  misjudges  his  distance  from  the 
ground  when  landing  and  flattens  out  too  soon  or  too 
late,  and  an  accident  may  easily  occur  before  the  mis- 
take is  realized.  In  the  air,  he  may  bank  too  much  or 
too  little  or  he  may  climb  on  a  turn.  Accidents  from 
attempting  to  make  turns  too  near  the  ground,  where 
a  side  slip  means  disaster,  are  notably  frequent. 

A  pilot  often  subconsciously  senses  a  danger  to 
which  he  is  subjected,  but  under  the  sudden  strain  of 
the  emergency  he  may  be  unable  to  think,  decide,  and 
act  quickly.  This  momentary  lapse  of  co-ordination 
between  reason  and  action  is  called  "loss  of  head/'  In 
flying,  a  fraction  of  a  second  often  counts  greatly,  and 
may  be  all  that  stands  between  safety  and  danger;  and 
in  an  emergency  there  is  seldom  time  to  correct  an  error. 

Loss  of  head  is  closely  associated  with  fatigue  and 
with  fear.  When  fatigued,  a  pilot  is  unable  to  think  and 
act  quickly,  because  his  brain  no  longer  responds,  with 
its  normal  promptness,  to  the  demands  that  are  made 
upon  it.  The  pilot  works  in  a  sort  of  stupor,  and  takes 
but  little  conscious  part  in  controlling  his  plane.  If  a 
crash  occurs  from  this  cause,  and  the  pilot  escapes, 
he  usually  has  no  distinct  recollection  of  what  happened 
during  the  flight; — his  memory  appears  to  have  been 
temporarily  stunned. 


AIRPLANE    ACCIDENTS 

£-is  closely  associated  with  fatigue  and  loss  of 
head,  but  it  does  not  appear  to  produce  many  acci- 
dents. There  is  little  time  to  think  of  danger  during 
flight,  and  consequently,  even  though  there  may  be  a 
sense  of  fear  lurking  somewhere  in  the  back  of  a  pilot's 
head,  it  rarely  asserts  itself  in  such  a  way  as  to  affect 
his  management  of  the  machine.  When  it  does,  how- 
ever, the  effects  are  similar  to  those  produced  by  loss  of 
head  and  fatigue. 

Courtesy  Air  Service,  U.  S.  A. 


? 


17 


A  RESULT  OF  DEFICIENT  VISION. 


FIRE  47 

Failure  of  the  Machine:  In  the  early  days 
of  flying,  accidents  were  frequently  caused  by  the 
failure  of  some  vital  part  of  the  plane,  but  this  difficulty 
has  now  been  largely  overcome.  There  is,  however,  a 
great  need  of  inspection  before  attempting  to  take  a 
machine  off  the  ground.  During  flight  the  plane  is 
subjected  to  severe  strain  and  vibration  and  its  parts 
are  likely  to  become  worn  or  loosened.  A  pilot  should 
always  see  that  his  airplane  is  mechanically  safe  before 
he  attempts  to  use  it,  and  the  subject  of  inspection  is 
discussed  in  some  detail  in  another  section  of  this 
book.  (See  page  36.) 

Fire:  It  is  not  uncommon  for  a  plane  to  catch 
fire  in  the  air,  and  investigations  of  several  accidents  of 
this  nature  show  that  defective  gasoline  feed  systems 
have  been  the  primary  cause.  It  has  developed  in 
some  cases  that  inadequate  drainage  of  the  fuselage  has 
allowed  an  accumulation  of  gasoline  immediately 
under  the  engine,  and  the  fumes  from  this  exposed  fuel 
catch  fire,  either  by  a  back-fire,  or  from  an  insufficiently 
protected  exhaust  manifold,  or  from  a  spark  from  one  of 
the  magnetos. 

There  is  always  more  or  less  free  gasoline  around  an 
aeronautical  engine, — coming  from  a  flooded  carbure- 
tor, a  leaking  feed-pipe,  or  some  other  source.  Ample 
drainage  facilities,  in  the  form  of  fair-sized  drainage 
holes  in  the  fuselage  bottom,  should  be  provided  so  as  to 
allow  the  oil  and  gasoline  to  drain  out  freely  when  the 
machine  is  in  any  possible  position.  The  entire  gaso- 
line supply  system  should  be  inspected  for  leaks 
before  every  flight,  and  any  leaks  that  may  be  found 
should  be  repaired  before  the  flight  is  attempted.  It  has 
been  demonstrated  that  there  is  less  likelihood  of  leakage 


48  AIRPLANE    ACCIDENTS 

occurring  in  the  gasoline  feed  system  if  the  supply 
tanks  are  connected  to  the  other  parts  of  the  system  by 
means  of  flexible  tubes  of  copper  or  other  material 
that  will  withstand  vibration. 

To  remove  the  fumes  of  gasoline,  the  engine  com- 
partment should  be  adequately  ventilated.  In  spite  of 
good  ventilation,  however,  there  is  always  a  possibility 
of  inflammable  vapors  remaining  near  the  engine,  and 
to  prevent  ignition  of  these  fumes  by  back-fires  it  is 
necessary  to  carry  the  open  end  of  the  carburetor 
air-intake  outside  of  the  engine  compartments.  With 
this  arrangement  flames  from  a  back-fire  are  blown  out 
into  the  open  air  instead  of  into  a  space  that  may  be 
filled  with  inflammable  fumes. 

As  a  protection  against  the  accidental  ignition  of 
inflammable  fumes  and  vapors  by  sparks  from  the 
magnetos,  it  appears  to  be  possible  and  practicable  to 
inclose  the  magnetos  on  aeronautical  engines  by  means 
of  gauze  covers  similar  to  the  kind  used  in  safety  lamps 
and  on  explosion-proof  motors  and  dynamos.  Pro- 
tection of  this  kind  might  not  prevent  fire  in  case  the 
magneto  became  drenched  with  liquid  gasoline,  but 
it  would  almost  certainly  prevent  the  accidental  igni- 
tion of  inflammable  vapors  in  the  engine  compartment, 
so  long  as  the  gauze  remained  whole  and  sound. 

To  prevent  a  fire  from  attaining  serious  propor- 
tions, a  pressure-actuated  sprinkler  system  has  been 
found  efficient  in  many  cases.  Such  systems  operate 
on  a  principle  similar  to  that  used  in  connection  with  the 
sprinkler  systems  found  in  large  buildings,  except  that 
the  fire-extinguishing  medium  in  the  airplane  is  not 
water,  but  pyrene,  fire-foam,  or  some  other  material 
effective  in  quenching  oil-fires,  and  that  the  system  is 


FIRE 


49 


w 


5O  AIRPLANE    ACCIDENTS 

actuated  by  air  pressure.  A  tank  is  installed  in  the 
airplane,  and  small  pipes  or  tubes  are  run  from  it  to 
various  parts  of  the  engine  compartment.  A  valve, 
actuated  by  the  release  of  a  fuse  of  soft  alloy,  is  pro- 
vided, and  when  a  fire  breaks  out  the  fuse  melts  and 
instantly  the  entire  engine  compartment  is  flooded  with 
an  effective  fire-extinguishing  spray.  The  main  ob- 
jection to  the  pressure  fire-extinguishing  system  is  that 
it  makes  considerable  additional  weight  for  the  airplane 
to  carry,  but  this  objection  is  offset  by  the  protection 
that  the  system  affords. 

The  danger  from  fire  is  not  confined  to  the  period 
of  actual  flight,  for  it  must  be  remembered  that  when 
a  "crash"  occurs  the  aviator  may  be  pinned  down  by 
the  wreckage  or  rendered  helpless  in  some  other  way, 
and  he  is  then  in  great  danger  if  the  wrecked  machine 
takes  fire. 

Airplane  fires  that  occur  in  consequence  of  crashes 
are  caused  largely  by  the  bursting  or  puncturing  of  the 
gasoline  tanks,  or  the  rupture  of  the  tubing,  from  the 
violence  of  the  impact.  In  most  airplanes  it  is  neces- 
sary to  carry  the  gasoline  under  pressure,  in  order  that 
the  fuel  may  reach  the  engine  when  the  machine  is 
"nosed  up"  at  a  considerable  angle.  When  the  gasoline 
tank  is  perforated  at  any  point  below  the  level  of  the 
liquid  surface,  the  air  pressure  forces  the  fuel  out  in  a 
fine  spray,  and  the  pilot,  passengers,  and  machine 
are  likely  to  become  drenched  with  it.  If,  as  frequently 
happens,  this  fuel  becomes  ignited  by  a  spark  from  any 
source,  the  results  are  usually  extremely  serious. 

Experiments  have  been  carried  on  with  the  intent 
of  producing  a  tank  that  will  not  burst  or  puncture  in 
a  crash,  or  which  will  not  distribute  the  gasoline  over 


FIRE  51 

the  machine  in  case  of  an  accident.  These  attempts 
have  been  fairly  successful,  and  safety  tanks  of  various 
kinds  are  now  available.  In  the  main,  safety  gasoline 
tanks  consist  in  a  metal  shell  of  medium  thickness, 
covered  with  fabric  and  vulcanized  rubber  of  varying 
degrees  of  elasticity.  The  whole  is  further  covered 
with  galvanized  wire  netting.  The  idea  is  to  provide 
a  flexible  form  of  construction  that  will  withstand 
severe  shock.  The  tubing  used  in  connection  with 
these  safety  tanks  should  be  of  soft  copper  or  other 
flexible  material.  It  is  altogether  probable  that  many 
of  the  fatal  airplane  accidents,  in  which  the  serious 
features  have  been  due  to  the  outbreak  of  fire  after 
the  crash,  could  have  been  prevented  or  rendered  far 
less  serious  if  safety  tanks  had  been  installed  on  the 
machines. 

To  prevent  the  spreading  of  fire  in  an  airplane, 
the  dope  used  on  the  fabric  should  be  as  nearly  fire- 
proof as  possible,  and  to  insure  greater  safety,  the 
cloth  also  should  be  fireproofed  before  the  dope  is 
applied  to  it.  Fire-resistive  dopes  have  been  produced 
in  various  ways,  the  most  common  method  being  by 
the  addition  of  certain  fire-retarding  substances  to  the 
ordinary  acetate  dope.  Many  of  the  dopes  prepared 
in  this  way  are  objectionable  on  account  of  the  fact 
that  they  are  much  heavier  than  ordinary  dope  and 
consequently  their  use  materially  increases  the  weight 
of  the  doped  surface.  Recent  developments  in  some  of 
these  fireproofing  methods,  however,  have  reduced  the 
added  weight  to  a  negligible  quantity. 

The  use  of  oils  and  varnishes  in  finishing  the 
woodwork  in  airplanes  increases  the  fire  hazard  in 
these  parts  considerably,  and  the  use  of  fire-resistive 


52  AIRPLANE    ACCIDENTS 

paint  on  all  interior  wooden  parts,  and  especially  in  the 
engine  compartment,  is  highly  desirable.  Fireproofing 
materials  may  be  a  little  more  expensive  than  the 
materials  ordinarily  used,  but  the  added  protection  that 
they  give  appears  to  be  well  worth  the  difference  in  cost. 

Superchargers  and  Variable-pitch  Propel- 
lers: For  use  in  flying  at  high  altitudes,  where  the 
air  pressure  is  considerably  below  normal,  superchargers 
and  variable-pitch  propellers  have  been  developed. 
Superchargers  compress  the  air  that  is  used  by  the  en- 
gine, and  deliver  it  to  the  cylinders  under  a  pressure 
that  is  approximately  the  same  as  that  prevailing  at  sea 
level.  Propellers  with  a  variable  pitch  can  be  so  chang- 
ed that  their  effect  on  the  rarefied  air  at  high  altitudes 
will  be  practically  the  same  as  that  of  normal  propellers 
on  the  air  at  sea  level.  Variable-pitch  propellers  might 
also  be  of  considerable  advantage  in  landing,  because  by 
reversing  the  pitch  the  head  resistance  of  the  airplane 
could  be  greatly  increased,  and  the  machine  could  be 
brought  to  a  stop  within  a  short  distance  after  the  wheels 
touch  the  ground.  The  practicability  of  the  variable- 
pitch  propeller  is  questioned  by  some  authorities,  how- 
ever, on  the  ground  that  any  mechanism  that  would 
vary  the  pitch  of  a  propeller  would  in  all  probability 
tend  to  reduce  the  solidity  of  the  propeller  as  a  whole. 
This  is  a  matter  worthy  of  serious  consideration. 

Instruments:  Although  well  trained  and  experi- 
enced pilots  and  mechanically  perfect  machines  are  the 
first  requisites  of  safety  in  flying,  various  other  factors 
are  also  of  great  importance  in  this  connection.  For 
example,  dependable  instruments  are  needed,  to  keep 
the  pilot  informed  with  respect  to  the  speed,  altitude, 
attitude,  and  direction  of  motion  of  the  airplane. 


INSTRUMENTS  53 

The  speed  of  the  airplane  is  read  from  an  air-speed 
indicator.  This  instrument  indicates  the  speed  with 
which  the  craft  is  moving,  relatively  to  the  air  through 
which  it  passes.  In  still  air  and  in  low  altitudes  the 
air-speed  meter  also  indicates  the  ground  speed  of  the 
craft  with  fair  accuracy,  but  if  the  wind  is  blowing  the 
ground  speed  must  be  calculated  from  the  reading  of  the 
instrument  and  the  velocity  and  direction  of  the  wind. 

The  direction  in  which  the  nose  of  an  airplane  is 
pointed  is  indicated  by  a  compass.  This  instrument  also 
enables  a  pilot  or  passenger  to  locate  objects  on  the 
ground  by  bearings,  when  the  position  of  the  plane  is 
known;  and  it  is  likewise  employed,  to  some  extent, 
for  determining  the  position  of  the  airplane  itself,  by 
taking  cross-bearings  upon  known  objects.  The  com- 
pass is  one  of  the  most  essential  of  all  airplane  instru- 
ments, and  one  that  is  most  likely  to  give  false  in- 
formation unless  particular  attention  is  given  to  its 
installation,  and  unless  the  readings  are  taken  while 
the  machine  is  flying  level  and  on  a  straight  course. 

The  altimeter  is  used  for  determining  the  height  of 
an  aircraft  above  the  surface  of  the  earth.  This  instru- 
ment is  usually  of  the  aneroid  barometer  type,  and  may 
be  either  indicating  or  recording  in  its  operation.  A 
bubble  statoscope  is  also  desirable,  to  indicate  short, 
rapid  changes  in  altitude,  too  small  to  be  shown  clearly 
on  the  altimeter.  Its  use  assists  a  pilot  in  holding  his 
machine  at  a  constant  level. 

The  purpose  of  the  inclinometer  is  to  show  at  what 
angle  the  airplane  is  flying, — indicating  the  lateral  as 
well  as  the  longitudinal  angle  that  the  plane  makes  with 
the  horizontal.  In  order  to  insure  the  effective  opera- 
tion of  an  inclinometer,  the  instrument  must  be  stabil- 


54  AIRPLANE    ACCIDENTS 

ized  by  a  gyrostat  or  other  equivalent  means,  and  all 
readings  must  be  made  when  flying  in  a  straight  line 
at  a  uniform  speed. 

In  planes  equipped  with  radio  apparatus,  the  radio 
directionfinder  is  rapidly  coming  into  use.  In  operat- 
ing this  device,  closed-coil  aerials,  fastened  in  the  wings 
of  the  machine,  are  used.  A  closed  flat  coil  possesses 
strong  directional  characteristics,  because  when  the  edge 
of  such  a  coil  is  pointed  directly  toward  the  incoming 
electrical  waves,  the  signals  received  are  of  maximum 
strength;  but  as  the  coil  is  turned  to  one  side  or  the 
other,  the  signals  rapidly  become  weaker  and  less  dis- 
tinct. With  a  radio  direction  finder  it  is  possible  to 
guide  an  airplane  with  considerable  accuracy  toward 
any  selected  radio  transmitting  station,  even  though 
the  station  is  entirely  invisible,  on  account  of  distance 
or  bad  atmospheric  conditions. 

Safety  Straps:  It  should  hardly  be  necessary 
to  emphasize  the  importance  of  using  safety  straps 
in  the  seats  of  airplanes,  but  experienced  aviators 
not  infrequently  fly  with  their  safety  straps  undone. 
Such  practice  is  foolhardy,  yet  it  would  be  easy 
to  mention  some  distinguished  aviators  who  have 
been  killed  by  carelessness  in  this  respect.  It  is  ab- 
solutely essential  that  the  pilot  and  passengers  in  air- 
planes be  strapped  to  their  seats,  to  prevent  falls 
when  the  machine  turns  on  its  side  or  on  its  back.  The 
straps  that  are  used  should  be  broad  and  exceedingly 
strong,  and  be  securely  fastened  to  the  framework  of 
the  machine.  The  device  employed  for  fastening  the 
belt  around  the  person  using  it  should  be  constructed 
so  that  it  can  be  released  quickly  and  with  one  hand; 
and  it  is  recommended  that  this  release  be  effected  by 


EMERGENCY    STATIONS  55 

means  of  a  small  hand  lever,  located  where  it  will  be 
easily  accessible  under  all  circumstances,  but  where  it 
cannot  be  operated  accidentally. 

Emergency  Stations:  Since  only  a  small  num- 
ber of  airplane  accidents  occur  outside  of  landing 
fields,  the  airdromes  are  the  scenes  of  the  greatest 
catastrophes.  A_  surgeon  should  be  employed  at 
every  permanent  landing  field,  to  furnish  assistance  in 
Case  of  accidents.  Every  airdrome  should  also  maintain 
an  emergency  station  and  an  ambulance,  and  a  number 
of  men  trained  in  first-aid  work  should  be  available 
to  assist  in  treating  injured  persons. 

The  emergency  station  should  be  well  supplied 
with  materials  necessary  for  treating  injuries  of  all 
kinds.  The  ambulance  should  carry  a  supply  of 
stretchers,  bandages,  splints,  surgeons'  plaster,  field 
dressings,  slings,  morphine,  hypodermic  syringes, 
anesthetics,  and  anesthetic  face-masks,  as  well  as 
scissors,  knives,  and  other  instruments  that  may  be 
needed  by  a  surgeon  in  field  work.  Wirecutters  (suit- 
able for  cutting  airplane  wires),  saws,  hammers,  crow- 
bars, and  other  tools  that  may  be  needed  for  clearing 
away  wreckage  should  also  be  carried  on  the  ambulance. 
Fire  extinguishers  are  likewise  essential. 

In  the  event  of  a  crash  or  a  bad  accident  of  some 
other  kind,  the  surgeon  and  a  staff  of  first-aid  men  and 
mechanics  should  proceed  with  the  ambulance  to  the 
scene  of  the  accident,  at  the  earliest  possible  moment. 
The  persons  involved  in  the  crash  should  be  removed 
from  the  wreckage  at  once,  and  placed  on  stretchers 
if  they  are  injured.  The  surgeon  should  make  a  rapid 
examination  of  the  injured  persons  and  direct  such 
first-aid  treatment  as  he  deems  advisable.  Only 


56  AIRPLANE    ACCIDENTS 

such  treatment  should  be  given  on  the  field  as  is 
necessary  to  relieve  pain  and  to  make  the  removal 
of  the  patient  safe. 

In  releasing  an  injured  person  from  the  wreckage, 
cut  away  the  debris  that  is  holding  him  down,  instead 
of  trying  to  drag  him  out.  Pulling  persons  from  the 
wreckage  may  convert  simple  fractures  into  compound 
ones,  and  add  materially  to  the  seriousness  of  the 
injury.  In  case  of  fire,  use  the  fire  extinguishers  on  the 
parts  near  the  injured  or  imprisoned  persons,  and  be 
careful  to  direct  the  streams  in  such  a  way  that  the  injured 
persons  will  not  be  suffocated  by  the  vapors. 

After  the  injured  and  other  persons  have  been 
removed  from  the  wreck,  a  corps  of  men  should  be 
assigned  to  take  the  damaged  plane  from  the  field. 
This  should  be  done  as  soon  as  possible,  because  any 
obstruction  remaining  on  the  field  may  seriously  inter- 
fere with  the  safe  operation  of  other  airplanes  using 
the  airdrome. 


IV.     PILOTS 


THE    IMPORTANCE    OF    LEGAL    REGULA- 
TION:     In  the  earlier  days  of  aeronautics,  little 
consideration  was  given  to  the  qualifications  that  a  man 
should  possess,  to  become  a  flyer.    Anyone  who  was  suf- 
ficiently daring  and  self-possessed  was  considered  fit  for 
the  work,   and  no  other  special   characteristics   were 
thought  to  be  necessary.    The  result  was,  that  many 
accidents  were  unexplained  and  there  was  an  enormous 
avoidable  waste,  both  of  men  and  of  machines. 

Under  present  conditions,  it  is  not  a  difficult  matter 
to  obtain  an  airplane-pilot's  license  from  the  Interna- 
tional Aeronautic  Federation, — an  organization  founded 
in  1905  for  the  purpose  of  regulating  aeronautics,  but 
confining  its  activities  to  the  control  of  aeronautic 
sports.  There  is  no  other  civilian  body  in  the  United 
States  that  issues  or  requires  licenses  at  the  present  time, 
save  in  a  few  states  and  municipalities  where  laws  or 
ordinances,  suggestive  of  those  established  in  connec- 
tion with  automobile  traffic,  have  been  enacted  for 
the  local  regulation  of  aeronautics.  With  these  excep- 
tions, and  with  the  important  additional  exception  of 


58  PILOTS 

X^1 

the  United  States  Air  Service,  the  operation  of  aircraft 
and  the  licensing  of  pilots  are  nowhere  officially  con- 
trolled or  provided  for. 

Relief  from  this  highly  unsatisfactory  condition 
of  affairs  is  promised  for  the  near  future,  however. 
The  United  States  has  declared  its  adherence  to  the 
International  Convention  Relative  to  Air  Navigation, 
and  as  a  sequence  to  this  action  Congress  will  doubtless 
take  appropriate  action  for  establishing  an  Air  Naviga- 
tion Commission,  and  drafting  rules  and  regulations 
affecting  aerial  navigation  in  general.  When  this  has 
been  accomplished,  air  pilots  will  probably  be  licensed 
by  the  Federal  Government,  in  accordance  with  some 
definite  plan  yet  to  be  determined. 

Pending  the  establishment  of  a  national  bureau 
for  carrying  on  this  work,  we  offer,  below,  some  con- 
structive suggestions  which  may  be  useful  to  local 
authorities  who  are  desirous  of  taking  immediate 
action  with  regard  to  air  navigation  and  the  licensing 
of  aerial  pilots. 

Physical  and  Mental  Qualifications  of  Pilots: 
Flying  does  not  require  a  super-man,  and  in  fact  a 
super-man  is  undesirable.  A  flier  must  be  normal  in 
every  way  and  any  variation  from  this  condition  re- 
duces his  ability  to  manage ,  a  flying  machine.  Many 
authorities  assert  that  if  the  machine  is  properly 
controlled,  flying  is  .not  much  more  hazardous  than 
riding  in  an  automobile;  but  even  if  this  were  true,  we 
must  surely  admit  that  the  act  of  providing  this  con- 
trol imposes  unique  demands  upon  the  pilot.  He  is 
the  heart  and  brain  of  the  airplane  and  it  has  been 
said  that  no  other  occupation  subjects  a  man  to 
strains  as  varied  and  intense  as  those  that  he  sustains 


QUALIFICATIONS 


59 


Courtesy  Air  Service,  U.  S.  A. 


TESTING  A  CANDIDATE'S  EYES. 


60  PILOTS 

while  operating  a  heavier-than-air  flying  machine. 
Moreover,  he  is  working  in  an  unnatural  environment, 
and  is  almost  wholly  unaware  of  its  effect  upon  his 
nervous  system.  The  machine  itself  may  fail  in  some 
part  and  still  be  brought  to  the  earth  without  serious 
injury;  but  if  the  pilot  relaxes  even  momentarily,  the 
whole  machine  is  without  a  director, — and  unless  it 
possesses  a  degree  of  stability  far  in  excess  of  that 
usually  provided,  it  may  easily  crash  to  the  ground. 

A  pilot  must  be  physically  and  mentally  fit  for 
his  work  before  he  is  taught  to  fly,  and  he  must  keep  in 
proper  physical  and  mental  condition  all  the  time  that 
he  is  engaged  in  aeronautical  work.  The  importance  of 
properly  selecting  the  men  who  are  to  engage  in  such 
activities,  and  the  desirability  of  keeping  these  men  in 
perfect  condition,  have  been  fully  demonstrated  by  the 
Medical  Department  of  the  United  States  Air  Service. 

A  pilot  should  be  at  least  nineteen  years  of  age, 
and  he  must  be  physically  perfect  in  every  way,— 
showing  no  abnormality,  congenital  or  otherwise,  that 
might  prevent  him  from  effectively  and  safely  opera- 
ting an  aircraft.  His  heart,  lungs,  kidneys,  and  nervous 
system  must  be  sound  and  healthy  and  capable  of 
withstanding  the  effects  of  prolonged  flight  and  of  rapid 
changes  of  altitude.  Moreover,  his  family  history 
should  show  no  inherent  ailments  or  diseases  of  a  nerv- 
ous type,  which  might  develop  quickly  in  his  own  case 
and  cause  a  temporary  or  permanent  mental  collapse. 

His  various  special  senses  should  be  normal  in 
every  way.  His  eyes  should  show  normal  stereoscopic 
and  color  perception,  and  his  general  field  of  vision 
should  be  good.  Persons  whose  eyes  show  more  than 
two  dioptrics  of  hypermetropia  (far-sightedness)  or 


TRAINING  6 1 

myopia  (near-sightedness)  should  be  rejected.  The 
middle  ear  should  be  healthy,  and  the  vestibular 
apparatus  should  be  intact  and  neither  more  nor  less 
sensitive  than  the  normal.  The  nose  should  show  free, 
air  passages  on  both  sides,  and  there  should  be  no  evi- 
dence of  any  serious  acute  or  chronic  affection  of  the 
upper  respiratory  tract. 

Training:  If  the  candidate  is  found,  by  ex- 
amination, to  conform  to  these  requirements,  he  is 
ready  for  his  aeronautical  training.  This  should  begin 
with  technical  instruction,  to  teach  him  the  principles 
involved  in  flying  and  to  make  him  entirely  familiar 
with  the  construction  and  operation  of  aeronautical 
engines  and  airplanes.  This  work  should  be  thorough, 
and  it  should  be  done  under  the  personal  guidance  and 
supervision  of  an  experienced  mechanician. 

When  the  technical  training  of  the  candidate  is 
satisfactorily  completed  and  he  thoroughly  under- 
stands the  operation  of  airplanes  and  aeronautical 
engines,  he  may  be  taught  how  to  fly.  In  connection 
with  flying  instruction,  an  ingenious  special  training 
apparatus  known  as  an  "orientator"  has  been  found 
to  be  extremely  useful.  It  consists  in  an  airplane 
cockpit  suspended  within  concentric  rings  or  gimbals, 
in  such  a  way  that  a  person  in  the  pilot's  seat  can  exe- 
cute any  manoeuver  that  can  be  accomplished  with 
an  airplane,  except  a  motion  of  translation.  He  can 
spin  around  in  any  way  whatsoever,  but  cannot  move 
in  a  straight  line  either  forward,  backward,  sidewise, 
or  up  or  down.  This  machine  can  be  used  by  the  avia- 
tor, with  entire  safety,  in  acquiring  a  tolerance  for 
vertigo,  and  in  learning  to  adapt  himself  to  the  rapidly 
changing  conditions  that  are  experienced  while  flying. 


62 


PILOTS 


Courtesy  Ruggles  Orientator  Corporation. 


AN  ORIENTATOR  IN  ACTION. 


LICENSING  63 

The  use  of  the  orientator  in  flying  schools  promises  to 
materially  shorten  the  time  of  flying  instruction,  and  to 
save  many  lives  and  many  machines. 

The  actual  flying  instruction,  in  the  free  air,  should 
be  given  in  a  dual-control  machine,  and  under  the 
direction  of  an  expert  flyer.  At  first  the  candidate 
should  do  but  little  of  the  actual  operating,  and  he 
should  never  be  allowed  to  manage  the  machine 
throughout  the  entire  flight,  until  he  has  thoroughly 
proved  his  efficiency  in  controlling  it.  Before  being 
allowed  to  ''solo"  (that  is,  to  fly  alone),  the  student- 
pilot  should  make  quite  a  number  of  flights  in  which  he 
does  all  of  the  actual  manipulating  of  the  machine, 
including  the  preliminary  inspection,  the  take-off, 
spirals,  turns,  spins,  glides,  dives,  and  landing,  accom- 
panied by  his  instructor  but  receiving  no  assistance 
from  him.  When  the  novice  has  demonstrated  in  this 
way  that  he  is  competent  to  fly,  he  should  be  allowed  to 
take  a  machine  up  alone;  but  his  flying  should  be. con- 
fined to  the  vicinity  of  the  airdrome  until  he  has  com- 
pleted at  least  eighty-five  hours  of  solo  work. 

Examination  and  Licensing:  When  the  stu- 
dent-pilot has  eighty-five  hours  of  solo  flying  to  his 
credit,  and  has  made  not  less  than  eighty  safe  land- 
ings, he  should  be  ready  to  qualify  for  a  commercial 
pilot's  license.  He  then  presents  himself  to  be  re- 
examined  physically  by  a  competent  medical  board,  and 
he  should  also  undergo  practical  tests  at  the  hands  of 
an  examining  board  composed  of  expert  flyers.  If  these 
boards  both  find  the  candidate  physically  qualified,  and 
competent  to  manage  an  airplane,  a  license,  bearing 
the  date  of  issue  and  valid  for  six  months  (except  in 
case  of  sickness  or  accident),  may  be  issued  to  him. 


64  PILOTS 

He  should  be  re-examined  every  six  months  thereafter, 
however,  and  if  he  is  still  found  to  be  physically  fitted 
to  fly,  the  date  of  the  re-examination  should  be  recorded 
on  his  certificate.  Re-examination  should  likewise 
be  made  after  every  illness  or  accident  that  the  aviator 
may  experience,  and  in  all  such  cases  he  should  be 
pronounced  physically  and  mentally  qualified  to  fly, 
before  being  allowed  to  resume  his  aerial  duties.  No 
pilot's  license  should  be  valid  for  more  than  six  months 
from  the  date  of  the  last  physical  examination. 

Care  of  the  Pilot's  Health:  In  the  larger 
permanent  airdromes,  where  a  number  of  pilots  are 
on  duty  or  in  training,  a  certified  physician  or  flight- 
surgeon  should  be  employed  to  supervise  the  recreation 
and  physical  training  of  the  aviators.  He  should 
study  the  habits,  temperament,  and  general  fitness  of 
each  individual  flyer,  and  act  as  a  medical  advisor 
to  whom  the  men  may  turn  for  counsel  in  time  of 
need.  An  aviator  may  be  suffering  from  some  tem- 
porary mental  disturbance,  for  example,  or  he  may  be 
slightly  out  of  condition  physically,  and  to  fly  under 
such  circumstances  might  spell  disaster.  In  cases  of 
this  kind  the  counsel  of  the  flight-surgeon  should  be 
sought  and  his  advice  followed. 

The  aviator,  if  he  is  to  maintain  his  highest 
efficiency,  must  be  careful  as  to  what  he  eats  and  when 
he  eats  it.  It  is  advisable  to  provide  a  special  eating 
place  for  pilots,  and  to  have  the  food  that  is  served  to 
them  prepared  under  the  direction  of  some  person 
who  thoroughly  understands  dietetics  and  food  values. 
College  athletes  have  "training  tables"  provided  for 
them,  and  an  aviator  surely  has  far  greater  reason 
than  they,  to  keep  himself  in  perfect  condition. 


THE   PILOT  S  HEALTH 


1-1      <3 


U 

w 

H 


66  PILOTS 

Rational  and  well-considered  exercise  is  essential 
to  the  maintenance  of  physical  and  mental  alertness, 
and  for  this  reason  special  flying  calisthenics,  particular- 
ly adapted  to  the  needs  of  aviators,  have  been  devised. 
These  exercises  should  be  executed  at  least  once  every 
day,  by  all  pilots,  and  preferably  under  the  direction  of 
the  flight-surgeon, — not  primarily  for  muscular  de- 
velopment, but  to  promote  rapid  and  accurate  co- 
ordination in  the  pilots'  mental  and  physical  activities. 


V.  THE  MAINTENANCE  AND  REPAIR 
OF  AIRPLANES 


THE  REPAIR  SHOP:  Emergency  repairs  are  us- 
ually made  by  the  airplane  pilot  or  his  mechanic, 
but  the  constant  strain  and  wear  caused  by  continued 
operation  also  cause  rapid  general  deterioration,  and 
this  makes  it  necessary  to  overhaul  every  airplane  fre- 
quently and  thoroughly.  The  engine  should  be  fully 
inspected  in  all  its  parts  after  every  50  hours  of  oper- 
ation, and  it  should  be  completely  overhauled  after  it 
has  operated  from  100  to  150  hours.  For  work  of  this 
kind  the  airplane  is  sent  to  the  repair  shop. 

Repair  shops  do  not,  in  general,  include  facilities 
for  making  large  castings  or  intricate  parts,  but  small 
aluminum  castings,  and  parts  that  are  ordinarily  made 
in  a  machine  shop  or  blacksmith  shop,  can  usually  be 
turned  out  in  the  airplane  repair  shop. 

The  parts  kept  in  stock  should  include  bolts,  nuts, 
cylinder  studs,  piston  rings,  rocker  arms,  hinge  pins, 
metal  sockets,  control-wire  guides,  longeron  clips, 
shock-absorber  guards,  and  in  fact  all  of  the  small 
fittings  used  in  airplane  construction. 

The  woodworking  section  of  the  repair  shop  should 


68 


MAINTENANCE    AND    REPAIR 


be  equipped  to  make  any  of  the  wooden  members 
found  in  a  plane,  including  longerons,  interplane  struts, 
rudder  posts,  tail  skids,  wing  skids,  spars,  compression 
and  former  ribs,  and  aileron  beams. 

In  repairing  airplanes,  a  systematic  course  should 
be  followed.  When  a  plane  comes  into  the  shop  for 
overhauling,  the  engine  should  be  removed  and  sent 
to  the  machine  shop.  The  rest  of  the  airplane  should 
be  thoroughly  inspected  and  tested,  and  parts  that  are 
found  to  be  weak  or  otherwise  defective  should  be 
removed  and  replaced  by  new  material.  Worn-out 
or  deteriorated  fabric  should  be  torn  off  and  replaced 
by  new.  The  landing  gear  should  be  carefully  examined 
and  rebuilt  if  necessary.  When  finished,  every  part 
should  be  tested  and  inspected  with  extreme  care. 

When    the   repairs    are    complete,    the   wings    are 

Courtesy  Col.  T.  H.  Bane  and  "Mechanical  Engineering." 


TESTING  A  LANDING  GEAR. 


REPAIR    SHOP    HAZARDS  69 

Courtesy  Col.  T.  H .  Bane  and  "Mechanical  Engineering." 


SAND-TESTING  A  FUSELAGE. 

alined  and  the  plane  is  assembled.  The  airplane  is 
then  given  the  correct  stagger,  incidence,  and  dihedral, 
and  is  thoroughly  air-tested. 

In  the  machine  shop,  the  engine  is  taken  down  and 
the  various  parts  are  thoroughly  washed  and  cleaned. 
Every  part  is  then  inspected  and  repaired  or  replaced, 
as  is  necessary.  When  this  has  been  done  the  engine 
is  rebuilt  and  thoroughly  tested  on  the  testing  block. 

Repair  Shop  Hazards:  The  making  of  ex- 
tensive repairs  on  airplanes  involves  practically  the 
same  hazards  as  those  encountered  in  airplane  manu- 
facturing; but  owing  to  the  fact  that  repair  shops  are 
usually  smaller  than  the  factories,  the  hazards  of  one 
department  are  likely  to  be  associated  more  or  less 
intimately  with  those  of  another,  because  the  work- 
rooms are  close  together,  and  in  some  instances  the 
various  operations  may  be  performed  in  the  same  room. 
The  hazards  that  exist  in  shops  under  normal  conditions 


7O  MAINTENANCE    AND    REPAIR 

were  increased,  during  the  war,  by  the  necessity  of 
realizing  a  high  speed  of  production,  by  the  unusual 
amount  of  night  work  that  had  to  be  done,  and  by  the 
impossibility  of  exercising  due  discrimination  in  the 
employment  of  labor.  In  fact,  the  exigency  of  the 
times  led  manufacturers  to  close  their  eyes  to  many 
unsafe  practices  and  conditions  that  would  not  be 
tolerated  under  normal  or  usual  conditions.  With  the 
return  of  peace  the  continuance  of  hazards  of  this 
kind  became  unjustifiable,  and  there  is  no  longer  any 
good  and  sufficient  reason  why  our  workshops  should 
not  be  made  reasonably  safe  in  all  respects. 

General  Fire  Prevention :  There  is  considerable 
danger  from  fire  in  an  airplane  repair  shop,  and  the 
entire  building  should  therefore  be  equipped  with  a 
powerful  and  efficient  sprinkler  system,  and  with  ade- 
quate standpipes  and  hose.  Hand  extinguishers  should 
also  be  provided  at  numerous  points  about  the  work- 
rooms, where  they  will  be  handy  and  available  at  all 
times.  It  is  important  to  see  that  the  water  supply  is  ful- 
ly adequate  to  meet  any  emergency  that  may  arise,  and 
that  a  good  water  pressure  will  be  constantly  available. 

To  prevent  the  spread  of  fire,  it  is  advisable  to 
subdivide  each  building  into  working  areas  as  small 
as  the  nature  of  the  work  will  allow.  This  may  be 
accomplished  by  building  fire-walls  where  space  permits; 
and  in  other  places,  where  the  floor  area  cannot  be 
subdivided,  fire  screens  may  be  placed  in  the  roof 
trusses, — extending  from  the  base  of  each  truss  to  the 
roof  planking.  These  screens  tend  to  prevent  the 
spread  of  flames  along  the  roof,  and  they  also  reduce 
the  horizontal  drafts;  and  in  both  these  ways  they 
materially  retard  the  progress  of  a  fire. 


WOODWORKING  71 

Woodworking:  The  framework  of  an  airplane 
is  usually  constructed  of  small  wooden  parts,  and  the 
repairing  of  this  skeleton  involves  the  hazards  usually 
associated  with  woodworking  processes.  The  amount 
of  waste  is  abnormally  large,  however,  because  only 
perfect  material  can  be  used,  and  considerable  quantities 
of  undesirable  stock  are  therefore  rejected. 

It  is  extremely  important  to  remove  all  waste 
material  from  the  workrooms  as  fast  as  it  is  produced, 
and  before  it  can  accumulate  in  any  quantity.  Blower 
systems  and  dust  collectors  should  also  be  installed  to 
remove  the  sawdust  and  fine  shavings,  and  dust- 

Courtesy  "U.  S.  Air  Service," 


A  WELL-REGULATED  WORKSHOP. 


72  MAINTENANCE    AND    REPAIR 

collecting  hoods  should  be  placed  on  all  machines  that 
produce  dust. 

The  wood-storage  area  should  be  well  separated 
from  the  main  buildings,  and  at  a  safe  distance  from 
railway  tracks  upon  which  steam  locomotives  operate. 
The  storage  areas  should  be  provided  with  ample 
hydrant  facilities,  and  equipped  with  suitable  hose. 

The  kilns  that  are  used  for  drying  the  wood  should 
be  separate  from  the  main  building,  and  the  practice 
of  drying  lumber  in  lofts  over  the  boiler-rooms  should 
be  abolished.  Kilns  should  preferably  have  brick 
walls  and  metal  roofs,  and  they  should  be  fitted  with 
stout  racks  of  steel  or  iron,  for  the  wood  to  rest  upon 
while  drying.  Caul  boxes  should  be  of  metal,  or  of 
wood  with  a  metal  lining. 

The  drying  material  should  never  be  allowed  to 
rest  upon  the  steam-pipes;  and  the  practice  of  using 
an  extended  smoke-pipe  for  heating  the  cauls  is  danger- 
ous and  should  not  be  allowed.  In  kilns  and  caul 
boxes  the  wood  should  always  be  kept  at  least  twelve 
inches  away  from  the  surfaces  from  which  the  heat  is 
obtained. 

The  airplane  framework  is  held  together  largely 
by  gluing,  and  this  frequently  involves  a  fire  hazard 
in  the  use  of  glue  heaters.  Flame  heaters  should  be 
eliminated  if  possible,  and  steam  or  electric  pots  should 
be  used  for  heating  the  glue.  The  use  of  glue  heaters 
can  be  avoided  by  using  casein  glue,  and  casein  glue 
is  rapidly  superseding  fish  glue  in  the  better  class  of 
airplane  work. 

In  repairing  the  fabric  covering  of  the  wings  and 
body  of  an  airplane,  a  considerable  amount  of  light, 
combustible  material  must  be  handled,  in  doing  the 


DOPING  73 

. 

necessary  cutting,  sewing,  and  fitting;  and  this  means 
that  there  is  a  considerable  fire  hazard  in  this  depart- 
ment. Work  involving  the  use  of  fabric  should  there- 
fore be  carried  on  in  an  isolated  building,  or  at  all 
events  in  rooms  separated  from  the  woodworking 
rooms  by  fire  walls. 

Doping:  For  the  purpose  of  making  the  fabric 
coverings  taut  and  waterproof,  they  are  covered  with 
a  special  sort  of  varnish,  after  they  have  been  fitted 
in  place  on  the  airplane  framework.  This  varnish 
(or  "dope"  as  it  is  called  in  the  trade)  varies  in  nature 
and  may  be  divided  into  three  kinds:  (i)  cellulose 
acetate  dissolved  in  a  solvent  containing  more  or  less 
tetrachlorethane;  (2)  cellulose  acetate  dissolved  in  a 
mixture  containing  no  tetrachlorethane  but  consisting 
mainly  of  methyl  acetate,  methyl-ethyl  ketone,  acetone, 
diacetone,  alcohol,  and  benzol;  and  (3)  cellulose  nitrate 
dissolved  in  a  mixture  of  butyl  acetate,  ethyl  acetate, 
alcohol,  and  benzol,  or  in  other  mixtures  containing 
varying  amounts  of  acetone,  amyl  acetate,  alcohol, 
methanol,  and  benzol.  Tetrachlorethane  is  not  much 
used  as  a  dope  solvent  at  the  present  time. 

When  dry,  the  nitrate  dope  has  properties  some- 
what similar  to  those  of  an  ordinary  moving-picture 
film.  It  burns  with  great  rapidity,  and  if  too  highly 
nitrated  it  may  also  be  explosive.  The  acetate  dopes 
are  far  less  inflammable  when  dry,  but  on  account 
of  the  inflammable  nature  of  most  of  the  solvents  that 
are  used,  they  burn  fiercely  when  in  the  dissolved 
state. 

The  greatest  danger  from  the  use  of  dope  lies, 
however,  not  in  the  fire  hazard  associated  with  it,  but 
in  the  poisonous  nature  of  certain  of  the  solvents  that 


74  MAINTENANCE    AND    REPAIR 

are  employed.  Tetrachlorethane,  for  example,  is 
extremely  dangerous,  and  its  fumes  seriously  affect 
the  liver  and  kidneys  and  the  muscles  of  the  heart. 
In  fact,  tetrachlorethane  is  one  of  the  most  poisonous 
of  the  chlorine  derivatives  of  the  hydrocarbons,  and 
permanent  destructive  changes  in  the  liver,  through 
fatty  degeneration,  are  more  marked  in  connection 
with  tetrachlorethane  inhalation  than  with  any  other 
substance  except  phosphorus. 

Benzol  probably  ranks  next  to  tetrachlorethane 
in  its  harmfulness, — severe  chronic  poisoning  from  this 
substance  invariably  producing  extensive  destruction 
of  the  white  corpuscles  of  the  blood,  and  not  infre- 
quently giving  rise  to  fatty  degeneration  of  the  liver, 
kidneys,  and  other  internal  organs.  Benzol  poisoning 
is  characterized  by  a  loss  of  weight  and  appetite,  a 
quick,  feeble  pulse,  a  bluish  appearance  of  the  skin, 
digestive  disorders,  general  weakness,  and  a  tendency 
to  fatigue  after  slight  exertion. 

Methanol  (wood  alcohol)  is  poisonous,  and  it 
causes  dilation  of  the  pupils  of  the  eyes,  blurs  the  sight, 
and  produces  abdominal  cramps,  nausea,  chills,  and 
drowsiness.  Instances  of  total  blindness  from  methanol 
poisoning  are  numerous,  and  fatal  cases  due  to  its 
absorption  are  not  uncommon. 

Chemically  pure  acetone  fumes  are  said  to  be  prac- 
tically harmless  when  inhaled  in  moderation;  but  the 
fumes  arising  from  impure  commercial  acetone  cause 
headache  and  a  burning  sensation  in  the  eyes. 

Amyl  acetate  has  a  slight  toxic  effect,  producing 
a  smarting  of  the  eyes,  dry  throat,  sensations  of  tight- 
ness in  the  chest,  and  a  tendency  to  cough.  It  also 
gives  rise  to  serious  nervous  and  circulatory  symp- 


DOPING  75 

toms  including  intense  pain  in  the  head.  On  account  of 
the  high  cost  of  this  substance  it  has  been  largely 
superseded  by  butyl  acetate  and  ethyl  acetate. 

Amy]  alcohol  is  said  to  be  four  times  as  poisonous 
as  methanol,  and  its  toxic  properties  have  been  es- 
timated to  be  five  times  as  great  as  those  of  ethyl 
alcohol  (/.  <?.  grain  alcohol).  It  acts  on  the  central 
nervous  system  and  also  produces  a  decided  drop  in 
blood  pressure. 

On  account  of  the  exceedingly  poisonous  nature  of 
tetrachlorethane,  dope  containing  this  substance  should 
never  be  used.  It  would  be  advisable  to  discontinue 
nitrate  dopes  also,  on  account  of  the  fire  hazard  as- 
sociated with  them,  though  it  is  not  likely  that  a 
radical  change  of  this  sort  can  be  brought  about  in  the 
near  future.  Doping  with  acetate  dope,  without  the 
use  of  tetrachlorethane,  may  be  carried  on  without 
any  extreme  hazard  if  a  proper  and  effective  ventilating 
system  is  used  in  the  rooms  where  the  work  is  done. 

Such  a  system  should  be  of  the  exhaust  type,  with 
powerful  suction  fans  to  draw  the  fumes  out  of  the 
room.  The  suction  outlets  should  be  located  in  or 
near  the  floor ',  and  it  is  best  to  make  the  floor  of  slat- 
like  construction,  and  to  draw  out  the  fumes  through 
the  spaces  between  the  slats.  The  vitiated  air  should 
be  discharged  into  the  open.  Inlets  for  fresh  air,  having 
an  aggregate  area  equal  to  at  least  three  times  the  area 
of  the  discharge  openings,  should  be  provided  at  points 
remote  from  the  outlets,  and  at  least  ten  feet  above  the 
floor  level.  Men  and  women  employed  in  the  doping 
room  should  be  instructed  to  conduct  their  work  in  such 
a  way  that  the  fumes  and  vapors  will  be  drawn  away 
from  them.  For  example,  in  applying  the  dope  the 


j  MAINTENANCE    AND    REPAIR 

workmen  should  begin  at  the  part  of  the  machine  that 
is  nearest  the  exhaust  outlet  (if  that  is  so  situated  that 
there  is  a  horizontal  current  of  air  in  the  room),  and 
work  towards  the  incoming  fresh  air.  It  is  just  as  easy 
to  do  this  as  it  is  to  work  in  the  opposite  direction,  and 
by  attending  to  this  simple  precaution  the  fume-ex- 
posure can  be  materially  reduced.  The  safest  places  in 
the  room  are  the  regions  near  the  fresh-air  inlets,  and 
the  workers  should  not  be  allowed  to  linger  needlessly 
where  the  fumes  of  the  dope  solvent  are  strong. 

Waste  material,  brushes,  containers,  and  wipe- 
rags  should  be  handled  with  care  and  kept  at  a  safe 
distance  from  every  heat  source,  to  reduce  the  chance 
of  their  catching  fire.  The  electrical  equipment  and 
wiring  should  be  so  arranged  and  protected  as  to  pre- 
vent the  possibility  of  fire,  and  no  open  switches  nor 
fuses  should  be  installed  in  the  workroom.  Vapor- 
proof  globes  should  be  used  around  the  incandescent 
lamps,  and  it  is  safest  to  locate  these  lamps  out-of- 
doors,  so  that  the  light  from  them  will  enter  the  work- 
room through  the  windows.  It  is  best  to  avoid  the  use 
of  pulleys  and  belts  in  doping  rooms,  but  if  they  must 
be  used  the  machinery  should  be  effectively  grounded 
to  .prevent  the  generation  of  static  electric  sparks.  It 
is  safest  to  ground  the  machinery  in  any  event,  and  if 
electric  motors  are  present  they  should  be  of  the 
special  vapor-proof  type. 

Machine  Shop:  It  will  not  be  necessary,  in 
this  place,  to  discuss  in  detail  the  general  hazards 
involved  in  ordinary  machine  shops,  because  we  have 
already  considered  them  in  another  special  book  en- 
titled "Safety  in  the  Machine  Shop"  copies  of  which 
may  be  had  upon  application  to  THE  TRAVELERS 


MACHINE    SHOP 


77 


INSURANCE  COMPANY.  We  shall  therefore  confine  our 
attention,  here,  chiefly  to  certain  special  hazards  that 
are  encountered  in  airplane  repair  shops. 

In  repairing  airplane  motors,  gasoline  is  used  in  con- 
siderable quantities,  for  cleaning  the  engines  and  engine 
parts.  Dip  tanks  and  spraying  systems  are  employed, 
and  there  is  often  a  copious  evolution  of  dense  gasoline 
fumes,  which  not  only  produce  a  bad  fire  hazard,  but 
also  gravely  endanger  the  health  of  the  workmen. 

The  cleaning  should  be  done  in  special,  isolated 
rooms,  ventilated  by  a  forced  exhaust  system,  and  but 
few  occupants  should  be  allowed  in  any  one  room. 
Special  precautions  should  be  taken  in  the  installation 
and  operation  of  electrical  apparatus,  as  described 
above,  and  reliable  means  for  extinguishing  oil  and 
gasoline  fires  should  be  provided.  The  use  of  respira- 
tors by  the  workmen  is  highly  recommended. 

Courtesy  Col.  T.  H.  Bane  and  "Mechanical  Engineering." 


' 


TESTING  AN  ENGINE. 

(This  engine  is  connected  to  an  electric  dynamometer  ) 


78  MAINTENANCE    AND    REPAIR 

Motor  Testing:  When  a  motor  is  to  be  tested, 
it  is  placed  on  a  testing  block  or  airplane  chassis 
and  a  propeller  is  attached.  Guards  should  be  installed 
in  front  of  the  propellers,  because  the  rapidly  revolving 
blades  are  extremely  dangerous  and  many  cases  are 
on  record  in  which  workmen  have  been  seriously 
injured  by  being  struck  by  them. 

As  a  number  of  machines  may  be  undergoing  test 
simultaneously,  oil  and  gasoline  are  often  present  in 
large  quantities.  Back-fires  are  numerous  and  they  are 
likely  to  start  a  conflagration.  Whenever  possible, 
testing  areas  should  be  located  in  open  fields,  at  consid- 
erable distances  from  the  nearest  buildings. 

When  inclosures  are  provided  for  testing  purposes, 
each  stand  should  be  separated  from  those  adjoining 
it  on  either  side  by  brick  or  concrete  walls,  and  each 
stand  should  be  covered  by  a  roof  of  metal  or  other 
fireproof  material, — the  ends  being  left  open.  When 
necessarily  located  inside  a  building,  the  testing  areas 
should  be  as  small  as  practicable,  and  separated  from 
the  adjoining  portions  of  the  building  by  safe  and 
substantial  fire  walls.  Hand-operated  fire  extinguishers, 
specially  adapted  for  use  in  connection  with  oil  and 
gasoline  fires,  should  be  maintained  in  each  compart- 
ment. Constant  care  should  be  exercised  to  keep  the 
area  as  free  from  combustible  material  as  possible, 
and  all  supplies  of  oil  and  gasoline  should  be  removed 
as  far  from  the  testing  areas  as  feasible,  and  should  be 
stored  and  handled  in  a  safe  and  approved  manner. 

In  some  instances,  aeronautical  engines  are  tested 
out  by  connecting  them  to  an  electric  dynamometer. 
Such  a  method  is  used  to  determine  the  horsepower 
that  a  motor  will  actually  develop  while  in  operation. 


VI.     LANDING  FIELDS,  AIRWAYS, 
AND  AERIAL  LAWS 


TANDING  FIELDS  IN  GENERAL:  Landing  fields 
JL/  may  be  divided  into  two  main  classes,  (i)  air- 
dromes and  (2)  emergency  fields.  Permanent  air- 
dromes are  large  fields  provided  with  hangars, 
repair  shops,  gasoline  stations,  and  accessories  of 
various  sorts.  Emergency  fields  are  smaller  than  air- 
dromes, as  a  rule,  and  are  used  only  in  case  of  forced 
landings.  They  should  be  numerous,  and  it  is  desirable 
to  have  them  located  at  short  intervals  along  every 
airway.  Municipal  fields  are  included  in  the  class  of 
permanent  airdromes. 

Airdromes:  An  ideal  airdrome  should  be  at 
least  3000  feet  square,  so  that  it  will  afford  ample 
landing  space  for  the  largest  planes.  Every  field 
should  have  a  straight  runway  at  least  1800  feet  long, 
in  every  direction  from  which  the  wind  is  likely  to  blow. 
This  should  be  regarded  as  the  minimum  admissible 
requirement,  because  if  a  motor  should  fail  in  leaving 
a  field  having  only  an  1 8oo-foot  runway,  there  would  be 
danger  of  an  accident  in  returning  to  the  ground.  A 
3OOO-foot  runway,  on  the  other  hand,  would  be  long 


8o 


LANDING    FIELDS 


Jt 


-,oooe 


Jt 


m 
i 


AIRDROMES  8 1 

enough  to  permit  the  average  pilot  to  take  a  machine 
off  and  still  remain  in  a  position  to  land  without  acci- 
dent if  the  motor  should  fail  in  climbing. 

The  proper  size  of  a  flying  field  depends  somewhat 
upon  the  nature  of  the  surrounding  country.  If  the 
land  in  the  vicinity  is  cleared  and  suitable  for  emergency 
landings,  the  need  of  an  airdrome  3000  feet  square  is 
not  so  urgent.  If,  however,  the  airdrome  is  surrounded 
by  tall  buildings,  or  if  the  adjacent  territory  is  of  such 
character  that  landing  on  it  would  be  dangerous,  safety 
considerations  may  demand  an  even  larger  amount  of 
space. 

In  choosing  the  site  for  an  airdrome,  an  effort 
should  be  made  to  find  a  place  that  can  be  easily 
reached,  and  one  that  is  not  likely  to  be  soon  surrounded 
by  buildings.  A  site  that  can  be  expanded  to  meet 
future  needs  is  highly  desirable,  and  it  should  be  so 
situated  that  transportation  facilities  are  accessible. 
Electric  power  and  a  water  supply  should  also  be 
available. 

The  best  shape  for  a  landing  field  is  a  square,  but 
a  T-shaped  or  L-shaped  field  will  suffice,  provided  it 
affords  a  runway  of  sufficient  length.  The  ground 
should  be  hard  and  firm  under  all  weather  conditions, — • 
a  light,  porous  soil  with  adequate  natural  drainage 
being  the  most  suitable.  Clay  soil  invariably  demands 
a  special  drainage  system  of  tiling,  to  prevent  the 
occurrence  of  unsatisfactory  conditions  in  wet  weather. 
The  field  should  be  smooth  and  level,  and  covered  with 
sod. 

Every  landing  field  should  bear  a  distinctive  sign 
of  some  kind,  easily  recognizable  from  the  air,  and  it  is 
also  desirable  to  have  the  name  of  the  city  marked  on 


82  LANDING    FIELDS 

the  ground.  A  white  circle,  100  feet  in  diameter,  has 
proved  highly  satisfactory  for  marking  purposes.  The 
line  forming  the  perimeter  of  the  circle,  and  the  lines 
constituting  the  letters,  should  be  three  feet  wide,  and 
the  letters  should  be  about  15  feet  square.  Permanent 
markers  can  be  economically  made  by  laying  out  the 
desired  design  on  the  ground,  digging  out  the  soil  to  a 
depth  of  six  inches,  and  filling  the  trench  or  excavated 
area  with  crushed  stone  coated  with  whitewash.  Fre- 
quent applications  of  whitewash  must  be  subsequently 
made,  to  keep  the  stone  white  and  visible  from  a  high 
altitude. 

Since  it  is  necessary  for  aviators  to  land  and  start 
against  the  wind,  a  large  wind  indicator  in  the  form  of 
a  standard  wind-cone,  or  a  white  cloth  "landing  T," 

Curtiss  Aero  Photo. 


AN  AIRDROME,  SHOWING  WIND  INDICATORS. 

(Note  that  the  wind  direction  as  indicated  by  the  white  T  is  not  the  same  as  that 
shown  by  the  wind-cone.) 


AIRDROMES 


THE  TYPE  OF  WIND-CONE  USED  AT  CURTISS  FIELD. 

should  be  placed  in  one  corner  of  the  landing  field. 
The  wind-cone  is  considered  the  more  reliable  because 
it  shifts  automatically  as  the  wind  changes,  whereas 
the  T  markers  have  to  be  moved  by  the  workmen. 
Wind-cones  are  flown  from  poles,  very  much  as  flags 
are  displayed.  Hangars,  repair  shops,  supply  houses, 
emergency  rooms,  and  gasoline  stations  should  be 
located  at  the  side  of  the  field,  in  places  where  they 
will  not  interfere  with  the  landing  and  taking  off  of 
the  aircraft. 

Provision  should  be  made  for  night  landings,  and 
to  this  end  large  searchlights  should  be  placed  where 
they  will  throw  a  flood  of  light  on  the  ground  of  the 
flying  field.  One  powerful  searchlight  that  will  throw 


04  LANDING   FIELDS 

a  beam  of  light  straight  upward  should  be  placed 
among  the  buildings  at  the  side  of  the  field.  A  beam 
of  this  kind  is  visible  from  a  high  altitude  on  clear 
nights,  and  on  foggy  nights  it  illuminates  the  clouds 
and  shows  (when  seen  from  above)  as  a  brilliant  white 
spot  in  the  mist. 

Every  airdrome  should  be  in  charge  of  a  superin- 
tendent, who  should  have  a  complete  staff  of  fieldmen, 
mechanicians,  riggers,  and  helpers.  The  superinten- 
dent's office  should  be  located  preferably  at  the  side  of 
the  field,  where  it  will  be  convenient  to  the  shops  and 
also  to  the  landing  area.  An  aviator  should  report 
to  the  superintendent  of  the  field  immediately  upon 
landing,  and  state  his  wants.  The  superintendent 
will  then  assign  the  necessary  men  to  take  care  of  the 
machine,  and  to  see  that  the  visitor's  needs  receive 
proper  attention. 


Curtiss  Aero  Photo. 


A  WELL-ARRANGED  AIRDROME. 


EMERGENCY    FIELDS  85 

Near  the  superintendent's  office,  the  emergency 
and  first-aid  station  should  be  established,  where  the 
surgeon  can  maintain  his  office  and  where  the  ambulance 
and  emergency  outfit  can  be  located.  A  lookout  should 
be  on  duty  outside  the  emergency  station,  and  should 
immediately  notify  the  surgeon  in  the  event  of  a  crash, 
or  a  serious  accident  of  any  kind.  In  case  of  a  minor 
accident  the  injured  person  should  be  treated  by  the 
surgeon  in  the  first-aid  room. 

Emergency  Fields:  Emergency  fields  are,  as 
the  name  implies,  fields  to  be  used  only  in  cases  of 
emergency  or  forced  landing.  They  need  be  only  about 
1500  feet  long  in  their  greater  dimension,  to  provide 
fairly  safe  landing  facilities.  All  that  is  really  necessary 
is  to  provide  sufficient  area,  level  and  free  from  trees 
and  other  obstacles,  to  afford  a  comparatively  safe 
landing  place  in  case  of  emergency.  Every  such 
field  should  be  provided  with  a  wind-cone,  however, 
to  indicate  the  direction  of  the  wind. 

It  is  highly  desirable  that  an  emergency  field  be 
provided  every  ten  miles  along  an  airway.  The  average 
airplane  can  glide  a  distance  equal  to  about  seven  times 
its  altitude,  so  that  a  plane  flying  at  a  height  of  5000 
feet  would  never  be  out  of  gliding  distance  of  a  landing 
field,  if  emergency  fields  were  situated  ten  miles  apart 
along  the  route. 

Airways  and  Air  Routes:  Air  routes  and  air- 
ways have  already  been  laid  out  to  some  extent, 
and  a  few  aeronautic  maps  have  been  drawn  up  to 
assist  the  aviator  in  finding  his  way  about  the  country. 
Airways  have  been  established  or  proposed,  extending 
across  the  continent  from  the  Atlantic  to  the  Pacific, 
and  some  have  been  laid  out  along  the  coast.  Airways 


/ 

86  LANDING    FIELDS 

are  transcontinental  and  coastal  in  extent,  while  shorter 
"air  routes"  interconnect  the  main  airways. 

Airways,  as  planned,  are  eighty  miles  in  width  and 
include  within  their  boundaries  the  principal  cities  along 
the  route.  Airdromes,  emergency  fields,  and  aerial 
mail  stations  are  rapidly  being  developed  along  the 
existing  airways  and  are  indicated  on  aeronautic  maps 
by  distinctive  markings. 

Aerial  Laws:  Aerial  Law  is  as  yet  a  new  and 
largely  undeveloped  subject.  The  extent  to  which 
aerial  navigation  has  developed  necessitates  the  es- 
tablishment of  a  strict  code  to  be  followed.  The  im- 
portance of  such  a  code  is  realized  and  the  problem  is 
receiving  serious  consideration. 

There  is  a  great  need  of  legal  regulation  of  landing 
fields,  both  public  and  private,  particularly  with  regard 
to  properly  restraining  visitors  and  sightseers  who 
come  to  the  field  for  the  purpose  of  looking  on.  Ex- 
perience shows  that  at  the  present  time  visitors  are 
permitted  to  roam  about  the  field  pretty  much  as  they 
wish,  and  they  are  exposed  to  dangers  (which  they  little 
appreciate)  due  to  the  landing  and  taking  off  of  aircraft. 
A  number  of  accidents  have  occurred  that  could  have 
been  avoided  if  certain  areas  had  been  set  aside  for 
flying,  and  certain  other  definite  areas  for  the  use  of  the 
public.  It  has  also  frequently  happened  that  rescue 
work  has  been  seriously  hampered,  after  an  accident, 
by  the  presence  of  a  large  crowd  on  the  field.  In  one 
instance  it  became  necessary  for  the  men  in  charge  of 
the  field  to  use  a  stream  from  a  fire-hose  to  keep  the 
crowd  away  from  a  wreck  sufficiently  to  allow  the 
rescue  party  to  liberate  the  injured  aviators. 

In  addition  to  laws  governing  the  establishment  and 


AERIAL    LAWS 

Courtesy  "Motor  Life."  Copyright  by  Kadel  and  Herbert,  N.  Y. 


AN  AERIAL  LIGHTHOUSE. 

use  of  landing  fields,  there  should  be  stringent  and 
effective  control  of  flights  over  centers  of  population. 
The  hazard  of  flying,  as  it  affects  the  person  on  the 
street,  in  his  home,  and  in  his  workplace,  is  far  greater 
than  is  generally  understood.  Laws  should  be  passed, 
protecting  the  innocent  population  from  exposure  due 
to  flights  over  cities,  especially  exhibition  work  and 
"stunting."  Under  ordinary  circumstances,  aircraft 
should  be  forbidden  to  pass  over  cities.  Prohibited  air 
channels  have  long  been  known  in  Europe. 


88  LANDING    FIELDS 

The  licensing  of  pilots  is  another  factor  that  should 
be  controlled  by  law.  (See  also  Section  IV,  page  57.) 
The  safest  airplane  in  the  world  becomes  unsafe  and 
highly  dangerous  in  the  hands  of  a  pilot  who  is  not 
mentally  and  physically  competent,  and  properly 
trained.  Legal  requirements  should  subject  pilots  to 
frequent  examination  as  to  their  fitness,  and  licenses 
should  be  issued  for  a  comparatively  short  period  of 
time.  At  the  end  of  this  period  the  aviator  should  be 
subject  to  re-examination,  as  we  have  stated  elsewhere. 
When  these  things  are  accomplished  it  can  be  said  that 
a  fair  start  has  been  made  toward  putting  aerial  nav- 
igation on  a  business  basis. 

Rules  of  the  air,  similar  in  nature  to  our  marine 
laws,  should  be  established  and  enforced.  Aeronautic 
maps,  similar  to  our  present  nautical  charts,  would 
provide  accurate  information  for  the  air  pilot,  and  a 
system  of  aerial  lighthouses,  marking  the  various  air 
routes,  would  be  of  great  assistance  to  aerial  navigation 
at  night.  Conspicuous  markers  along  the  traveled  air 
routes  would  serve  the  aeronaut  in  much  the  same  way 
that  a  mariner  is  now  assisted  by  the  spars  and  buoys 
found  in  our  navigable  waters;  and  the  systematic  send- 
ing out  of  wireless  directional  signals  from  important 
.airdromes  would  also  tend  strongly  to  insure  safety. 


VII.     METEOROLOGICAL  SERVICE 


REALIZING  the  need  for  information  regarding  the 
weather  conditions  in  the  higher  altitudes,  the 
United  States  Weather  Bureau,  in  co-operation  with 
the  various  government  flying  fields,  now  furnishes  data 
of  this  kind.  Reports  forecasting  the  weather  conditions 
for  the  next  twenty-four  hours  are  prepared  daily  and 
sent  to  the  various  flying  fields  about  the  country. 

In  gathering  the  data  from  which  these  reports  are 
made,  kites,  kite  balloons,  airplanes,  and  small  rubber 
balloons,  whose  course  through  the  air  may  be  followed 
by  the  use  of  theodolites,  are  employed.  The  direction 
and  velocity  of  the  wind  at  various  altitudes,  together 
with  the  temperature  of  the  air  and  the  height  of  cloud 
formations,  are  noted.  These  records  are  made  twice 
daily,  and  from  them  bulletins  are  prepared,  giving  the 
current  and  probable  future  atmospheric  conditions  at 
altitudes  of  250,  500,  1000,  2000,  3000,  and  4000  meters. 

The  country  is  divided  into  zones,  and  the  flying 
fields  in  each  zone  receive  the  bulletins  forecasting 
weather  conditions  for  their  vicinity.  To  aid  pilots 


9O  METEOROLOGICAL    SERVICE 

flying  from  one  zone  to  another,  special  reports  may  be 
obtained  upon  request,  covering  the  probable  conditions 
over  the  entire  route.  Requests  for  such  reports  should 
include  the  name  of  the  starting  point,  the  destination, 
the  route  to  be  followed,  and  the  time  of  contemplated 
departure. 

Before  starting  a  flight  of  any  kind,  a  pilot  should 
find  out  what  conditions  he  is  likely  to  meet  aloft. 
The  conditions  on  the  ground  afford  but  small  indica- 
tion of  what  is  to  be  met  with  in  the  upper  air,  and  no 
reliable  information  regarding  the  conditions  at  the 
higher  altitudes  can  be  obtained  unless  measurements 
and  observations  are  taken.  This  work  is  also  done  for 
the  aviator  by  the  Weather  Bureau,  and  he  merely  has 
to  ask  for  the  information,  at  the  nearest  weather  sta- 
tion or  flying  field. 

At  certain  of  the  meteorological  stations,  special 
upper  air  investigations  are  being  carried  on,  and  the 
activities  at  these  stations  have  made  it  necessary  to 
restrict  the  areas  near  by.  During  clear  weather  an 
aviator  might  see  the  kites  and  other  kinds  of  apparatus 
in  the  air,  but  even  under  favorable  atmospheric  condi- 
tions they  cannot  be  seen  at  any  considerable  distance, 
and  in  cloudy  weather  or  in  semi-darkness  they  are 
not  visible  at  all;  and  if  a  plane  should  collide  with  the 
kites,  or  with  the  wires  by  means  of  which  they  are 
flown,  serious  damage  would  be  likely  to  result. 

Aviators  are  therefore  warned  not  to  fly  above 
the  stations  at  which  work  of  this  kind  is  being  done. 
They  are  located  at  the  following  points:  Broken 
Arrow,  Oklahoma;  Drexel,  Nebraska;  Due  West,  South 
Carolina;  Ellendale,  North  Dakota;  Groesbeck,  Texas; 
and  Royal  Center,  Indiana. 


VIII.     AIRCRAFT   INSURANCE 


TIMITED   CHARACTER    OF    THE    FIELD:      A 

JL'  consideration  of  aircraft  insurance  naturally 
begins  with  an  inquiry  respecting  the  field  for  such 
insurance.  This  field  appears  to  be  limited,  at  the 
present  time,  to  the  heavier-than-air  machines,  and 
the  number  of  these  that  are  employed  in  commercial 
activities  (as  distinguished  from  exhibition  and  sport 
purposes)  is  still  quite  small. 

Lighter-than-air  machines  have  not  yet  been 
developed  to  a  point  where  they  are  used  to  any  extent 
for  private  and  commercial  purposes,  and  they  are 
not  considered  to  be  within  the  field  of  aircraft  in- 
surance. The  reasons  for  this  are  many,  but  prominent 
among  them  are  the  difficulty  and  expense  of  equipping 
and  maintaining  a  lighter-than-air  machine,  and  the 
unreliability  and  grave  danger  attendant  upon  the  use 
of  inflammable  gas  as  a  means  of  overcoming  the 
force  of  gravity.  There  is  some  promise  that  airships 
buoyed  up  wholly  or  partly  by  gas  will  sooner  or  later 
be  developed  to  the  point  of  practicability  for  private 
and  commercial  use,  and  if  they  can  be  rescued  from 


92  AIRCRAFT   INSURANCE 

their  present  unusual  hazards,  a  great  field  of  usefulness 
can  be  found  for  them,  because  in  many  respects  they 
have  an  advantage  over  the  other  class  of  aircraft. 

Speaking  broadly,  the  field  for  aircraft  insurance 
is  yet  to  be  developed,  because  the  aircraft  themselves 
are  yet  to  be  manufactured  and  sold.  The  aircraft 
now  available  for  private  and  commercial  use  are  largely 
of  the  training  type,  and  not  fitted  nor  intended  for 
long-distance  flights.  Strange  as  it  may  appear,  the 
large  majority  of  the  aircraft  now  available  for  private 
ownership  are  much  safer  when  used  reasonably  for 
exhibition, — even  including  so-called  "stunt  flying,"- 
than  they  would  be  for  long  distance  flights,  as  a  general 
rule.  Of  course  manufacturers  are  developing  new 
types  of  airplanes,  but  at  the  present  time  the  available 
aircraft  are  chiefly  used  in  enterprises  that  do  not 
furnish  an  attractive  field  for  aircraft  insurance  and  the 
field  at  the  present  lies  largely  in  the  realm  of  conjecture. 

The  Development  of  Transportation :  A  rail- 
road train,  seventy-five  or  eighty  years  ago,  was 
more  of  a  curiosity  than  an  airplane  is  now.  In 
those  days  small  model  trains,  running  on  circular 
tracks,  were  exhibited  at  county  fairs  and  a  fee  was 
charged  to  see  the  side  show.  Railroads,  however, 
offer  no  opportunities  for  sport  use,  and  their  develop- 
ment was  unhindered  by  any  misapplication  of  their 
purpose.  The  railroad  has  become  an  absolute  public 
necessity  and  an  important  feature  in  our  lives. 

A  number  of  years  later,  the  trolley  car  was 
developed.  In  the  early  days  a  passenger  often  refused 
to  pay  fare  on  one  of  these  cars  until  it  reached  the 
point  at  which  he  wished  to  alight,  because  too  often 
it  did  not  reach  that  point.  Something  was  happening 


DEVELOPMENT  OF  TRANSPORTATION        93 

all  the  time,  and  judging  by  the  experiences  of  those 
days,  it  seemed  that  there  would  never  be  such  a  thing 
as  a  successful  trolley  system  in  the  country. 

Then  came  the  automobile,  and  the  history  of  its 
development  is  so  recent  that  comment  is  hardly 
necessary.  One  incident  of  the  early  days  of  automobiles 
is  recalled,  in  which  a  party  undertook  a  run  from 
Hartford,  Connecticut,  to  New  Britain,  a  distance  of 
nine  miles.  A  repair  man  and  a  car  loaded  with  tools 
and  appliances  was  taken  along,  to  help  out  any  cripples 
that  might  be  picked  up  on  the  way.  The  repair 
car  broke  down,  but  fortunately  the  other  cars  reached 
their  destination  in  safety. 

For  the  first  time  since  we  had  to  depend  upon  the 
horse,  we  had  found  a  means  of  land  transportation  that 
could  also  be  devoted  to  sport  purposes,  and  it  promptly 
was  so  devoted,  with  the  result  that  the  development 
of  the  automobile  was  delayed  by  its  misapplication. 
A  speed  craze  took  hold  of  the  people.  Automobile 
racing,  exhibitions,  and  tricks  became  prominent  in  the 
early  days  of  that  means  of  transportation,  and  for  a 
time  these  features  promised  to  overshadow  the  really 
serious  personal  and  commercial  uses  to  which  auto- 
mobiles could  be  put.  In  its  early  days  the  automobile 
was  cordially  hated  by  a  vast  majority  of  the  people, 
particularly  in  rural  communities;  but  it  survived  and 
to-day  it  is  found  in  almost  countless  numbers  in  all 
communities.  It  has  come  to  be  a  necessity,  and  the 
people  at  large  probably  feel  that  they  cannot  dispense 
with  its  use. 

Possibilities  and  Limitations  of  Aircraft: 
In  the  automobile  as  a  means  of  transportation,  we 
find  something  which  more  closely  approximates  the 


94  AIRCRAFT    INSURANCE 

• 

aircraft  than  any  other  present  form  of  transporta- 
tion, particularly  by  land.  The  all-important  ques- 
tion from  the  insurance  standpoint  is,  will  the  history 
of  railroads,  trolleys,  and  automobiles  be  repeated 
in  the  future  history  of  aircraft?  The  automobile 
survived  its  purely  personal  and  sport  uses,  and  has 
developed  into  a  commercial  necessity.  Will  aircraft 
do  the  same  thing?  We  can  make  no  positive  answer 
at  present,  but  we  can  reason  toward  an  answer  by  ex- 
amining some  of  the  claims  that  can  be  made  in  behalf 
of  aircraft  as  a  means  of  transportation. 

Prominent  among  those  claims  is  the  matter  of 
speed.  The  speed  which  has  been  obtained  in  airplanes 
is  already  phenomenal,  and  the  possible  speed  of  the 
future  is  beyond  conjecture;  but  speed  is  not  the  only 
consideration.  If  a  man,  under  urgent  business  require- 
ments, can  actually  fly  from  New  York  to  Chicago  in 
eight  or  ten  hours  when  transportation  by  train  would 
require  more  than  twice  that  time,  that  looks  attractive 
on  its  face,  and  it  looks  as  though  airplanes  might  be 
developed  as  a  means  for  the  rapid  transportation  of 
passengers;  but  we  must  go  a  step  further  and  consider 
the  fact  that  a  trip 'from  New  York  to  Chicago  in  a 
given  number  of  hours  is  only  a  part  of  the  story.  The 
railroad  stations  in  New  York  and  Chicago  are  acces- 
sible, and  when  a  passenger  arrives  at  a  railroad  station 
there  are  convenient  means  of  local  transportation  by 
the  use  of  which  the  traveler  can  reach  his  actual 
destination  speedily.  It  is  not  so  with  the  airplane  at 
present.  If  a  man  in  the  business  center  of  Chicago 
desires  to  travel  by  airplane  to  New  York,  he  must 
first  journey  to  an  outlying  field  which  will  necessarily 
be  in  the  suburbs,  and  not  necessarily  within  convenient 


DANGERS    OF    AERIAL    TRANSPORTATION  95 

reach  by  means  of  short  local  travel.  Therefore,  a 
fair  portion  of  the  time  that  is  apparently  saved  by 
the  airplane  is  spent  in  getting  to  a  starting  place.  Then 
when  he  arrives  at  New  York,  the  same  situation  is  en- 
countered. Perhaps  he  may  land  at  Mineola  or  some- 
where else  on  Long  Island,  and  then  have  to  use  up  an 
hour  or  more  in  traveling  from  that  place  to  his  actual 
destination  in  the  business  district  of  New  York  City. 
In  this  aspect  the  allurement  of  the  airplane  loses  some 
of  its  force  because  the  time  actually  saved,  even  if  the 
trip  be  accomplished  without  mishap,  is  much  less  than 
it  appears  to  be  on  the  face  of  the  record; — all  of  which 
goes  to  show  that  before  the  airplane  can  be  recognized 
as  a  suitable  and  necessary  means  for  rapid  transporta- 
tion, landing  facilities  must  be  provided  with  means  of 
rapid  transportation  to  business  centers  in  the  various 
cities  of  the  country.  Up  to  the  present  moment  no 
substantial  progress  has  been  made  in  that  direction, 
and  all  of  this  militates  against  the  development  of  the 
airplane,  and  consequently  against  the  development  of 
the  field  for  aircraft  insurance. 

The  Dangers  of  Aerial  Transportation:  The 
dangers  of  airplane  transportation  have  in  the  past 
deterred  a  great  many  people  from  accepting  that 
means  of  travel,  and  will  probably  continue  to  de- 
ter them  in  the  future.  These  dangers  may  be 
largely  exaggerated.  The  railroads,  the  trolleys, 
and  the  automobiles  have  left  behind  them  in  the 
course  of  their  development  a  long  trail  of  dead  and 
injured,  and  the  fact  that  airplane  transportation  is 
dangerous  probably  will  not  of  itself  seriously  delay 
the  development  of  such  transportation,  if  other  ob- 
stacles are  removed. 


96  AIRCRAFT   INSURANCE 

During  the  war  the  men  who  were  trained  in  this 
country  for  aviation  duties  were  trained  upon  fields 
that  were  more  or  less  congested,  and  with  machines 
that  were  more  or  less  deficient.  If  available  figures 
are  correct,  we  must  admit  that  even  under  the  unusual 
conditions  attendant  upon  war  training,  and  the  unusual 
hazards  due  to  an  undeveloped  machine,  there  was  only 
one  fatality  in  nearly  3000  hours  of  flight;  and  3000 
hours  of  flight  under  favorable  conditions  and  at  a 
fairly  moderate  speed  would  take  an  aviator  seven  or 
eight  times  around  the  world,  if  such  a  thing  were 
practically  possible.  There  are  reasons  for  believing 
that  the  frequency  of  fatal  accidents  in  private  and 
commercial  use  would  be  much  lower  than  the  fre- 
quency recorded  during  the  period  of  war  training, 
when  all  surrounding  conditions  are  considered. 

Figures  compiled  by  the  United  States  Air  Service 
covering  a  period  of  six  months  during  the  war  show 
that  only  about  2^  per  cent,  of  all  accidents,  both 
fatal  and  non-fatal,  were  due  to  failure  in  the  plane 
construction  or  its  parts.  The  same  tabulation  shows 
that  in  the  event  of  injury  where  a  machine  carries  a 
pilot  and  one  or  more  passengers,  the  pilot  is  the  most 
likely  to  escape. 

Making  Insurance  Rates:  In  the  consider- 
ation of  accident  characteristics  in  airplanes  for  the 
purpose  of  reaching  rate  results,  it  has  been  assumed 
that  the  proportion  of  fatal  and  permanent  total  injuries 
to  the  total  number  of  injuries  would  be  far  larger  than 
it  is  in  ordinary  casualty  lines.  Whether  this  theory 
will  prove  true  in  practice  or  not  remains  to  be  seen; 
but  in  the  absence  of  reliable  data  respecting  this  partic- 
ular feature  it  seems  reasonable  to  assume  that  in  the 


UNRELIABILITY    OF    AIRPLANES  97 

distribution  of  accidents  as  to  results,  cases  involving 
fatal  and  permanent  total  disability  will  occur  in  great- 
er proportion  than  similar  cases  in  other  lines. 

Another  theory  has  been  employed  in  developing 
compensation  rates  particularly,  and  that  is,  that  in  the 
event  of  fatal  injuries  the  proportion  of  those  found 
to  be  without  dependents  will  be  larger  among  airplane 
pilots  than  in  the  ordinary  compensation  lines.  This 
is  conjecture  almost  entirely. 

The  laws  of  many  states  requiring  payment  into 
a  special  fund  in  cases  where  there  are  no  dependents 
will  offset  this  conjecture  to  a  considerable  degree.  So 
far  as  is  known,  there  are  no  data  of  any  moment  which 
would  serve  to  either  prove  or  disprove  this  theory, 
but  it  has  been  used  almost  from  necessity  in  order 
to  produce  an  airplane  rate  (particularly  for  compen- 
sation) which  was  not  on  its  face  prohibitive,  and 
which  would  not  obstruct  the  progress  of  this  new 
means  of  transportation. 

Unreliability  of  the  Airplane:  The  next  fea- 
ture which  apparently  weighs  against  the  growth 
of  the  airplane  as  a  means  of  transportation  is  the 
unreliability  of  the  machine,  as  compared  with  other 
agencies  that  travel  on  the  land  or  the  sea.  Per- 
haps the  airplane  does  not  differ  much,  in  this  respect, 
from  the  automobile  in  its  earlier  history,  or  even 
from  the  railroads  or  trolleys.  Stability  and  dependa- 
bility are  matters  of  development,  and  if  we  have  due 
faith  in  the  inventive  genius  of  our  people,  we  may 
with  reason  conclude  that  present  conditions  in  this 
respect  will  be  materially  improved,  if  not  largely 
cured,  in  the  near  future.  We  may  even  now  note 
that  the  alleged  instability  of  the  present  airplane  is 


9o  AIRCRAFT    INSURANCE 

not  abundantly  demonstrated  by  the  evidence.  During 
the  two  years  or  more  that  airplanes  have  been  used  for 
carrying  mail,  practically  ninety-five  per  cent,  of  the 
contemplated  trips  have  been  successfully  flown.  This 
performance  is  regarded  as  unusually  creditable,  because 
during  the  winter  months  the  flying  was  done  under 
specially  trying  conditions,  and  many  of  the  planes  had 
to  be  equipped,  for  weeks,  with  snow  skids  in  place 
of  wheels. 

The  Cost  of  Airplanes:  Airplanes,  so  far 
as  they  are  available,  can  be  purchased  at  almost  any 
price  that  a  person  is  willing  to  pay;  but  a  heavier- 
than-air  machine  capable  of  carrying  as  much  as  a 
ton  of  merchandise  (in  addition  to  the  pilot,  crew, 
instruments,  fuel,  and  other  necessary  sources  of 
weight)  would  certainly  be  a  large  and  expensive  ap- 
paratus. We  cannot  say  what  the  cost  would  be,  but 
it  would  no  doubt  materially  exceed  $25,000.  Here 
the  lighter-than-air  machine  would  have  many  ad- 
vantages, because  in  construction  (outside  of  the  gas 
supply)  it  would  probably  be  less  expensive.  Therefore, 
when  the  gas  supply  problem  is  settled  (if  it  ever  is) 
the  field  for  the  lighter-than-air  machine  will  probably 
be  found  to  consist  in  the  transportation  of  dead 
weights,  where  sustained  speed  is  not  of  any  special 
importance. 

We  know  very  little  at  present  about  the  cost  of 
maintenance  and  repair,  although  we  have  a  general 
understanding  that  it  is  pretty  large.  An  engine  used 
in  an  airplane  is  capable  of  perhaps  500  hours  of 
service,  although  it  is  customarily  removed  and  over- 
hauled after  a  far  shorter  period. 

Very  little  is  known  about  the  cost  of  fuel.     Some 


WHY    WRITE    INSURANCE?  99 

rather  reckless  statements  have  been  made  respecting 
fuel  cost,  as  well  as  the  cost  of  repairs  and  allowances 
for  depreciation;  but  the  sum  total  of  the  whole  situa- 
tion appears  to  be,  that  the  initial  cost,  when  combined 
with  the  cost  of  maintenance  and  use,  is  at  the  present 
time  nearly,  if  not  quite,  prohibitive;  and  unless  this 
obstacle  can  be  reasonably  reduced,  the  development 
of  the  airplane,  for  commercial  purposes  at  least,  will  be 
slow.  However,  we  are  reminded  of  the  apparently 
unanswerable  objections  that  were  advanced  only  a 
few  years  ago  respecting  the  automobile,  and  we  do 
not  forget  how  successfully  the  claims  respecting  ex- 
cessive cost,  not  only  as  to  the  original  purchase  price, 
but  as  to  maintenance  and  use,  have  been  dealt  with. 
The  economy  of  transportation  by  automobile  truck 
has  been  adequately  demonstrated,  as  is  evidenced  by 
the  constantly  growing  use  of  these  vehicles. 

Why  should  Aircraft  be  Insured?  The  next 
question  is,  why  should  aircraft  insurance  be  un- 
dertaken by  casualty  companies?  Here  an  entirely 
different  line  of  reasoning  is  encountered.  It  is  well 
known  that  in  spite  of  all  delays  and  hindrances,  a 
large  number  of  airplanes  are  actually  in  operation  in 
various  parts  of  the  country.  These  machines  are 
mostly  owned  by  the  government,  and  operated  either 
by  the  army  or  navy,  or  by  the  mail  service;  and 
operations  of  this  kind  obviously  do  not  come  within 
the  field  of  insurance.  After  all,  however,  there  are 
some  airplanes  left.  There  are  such  things  in  service 
as  private  and  commercial  airplanes.  Their  use  in 
many  instances  involves  the  employment  of  pilots  and 
of  others  who,  in  the  course  of  their  duties  as  employees, 
are  required  to  fly;  and  in  such  cases  the  compensation 


100 


AIRCRAFT    INSURANCE 


A  SEAPLANE  CRASH. 

(This  photo  was  taken  at  the  instant  the  plane  struck  the  ground.) 


AFTER  THE  ACCIDENT. 

(This  seaplane  crashed  on  a  beach  filled  with  recreation  seekers.    The  pilot  and  his  two 
passengers  were  killed.) 


NATURE    OF   THE  ,GO#TiRA1GTS  A101 

laws  in  most  of  our  states  require  insurance  (or  other 
satisfactory  security)  for  the  compensation  obligation. 
In  other  words,  if  the  owners  of  airplanes  in  civil  life 
have  employees,  the  law, — in  a  great  many  instances 
at  least, — requires  them  to  obtain  insurance.  There 
are  many  reasons  for  claiming  that  insurance  companies 
professing  to  write  compensation  lines 'would  fail  in 
their  duty  if  they  did  not  devise  means  for  providing 
insurance  in  this  line  also,  inasmuch  as  the  law  requires 
the  employer  to  provide  himself  with  it.  Therefore, 
perhaps  the  first  reason  why  aircraft  insurance  has  been 
undertaken  is  that  it  is  the  duty  of  insurance  companies 
to  provide  it  or  to  devise  means  through  which  it  can 
be  secured.  These  considerations  apply  to  workmen's 
compensation  insurance  only,  but  a  company  under- 
taking this  line  would  naturally  conclude  that  there 
should  go  with  it  such  other  lines  as  its  corporate 
powers  would  allow  it  to  write,  and  which  would  serve 
to  increase  premium  receipts  and  to  an  extent  improve 
the  distribution  in  a  necessarily  limited  field.  In- 
cluded in  that  program  would  be  public  liability  and 
property  damage,  as  well  as  individual  accident  in- 
surance for  passengers  and  others  exposed  to  the  hazard 
of  flying. 

Nature  of  the  Insurance  Contracts:  The 
public  liability  and  property  damage  lines  are  in  some 
respects  similar  to  the  corresponding  lines  now  under- 
taken, by  many  casualty  companies,  in  connection 
with  automobiles.  They  differ,  however,  in  one  es- 
sential particular,  which  is,  that  public  liability  pol- 
icies do  not  ordinarily  cover  the  passenger  hazard. 

The  passenger  hazard  may  be  covered  by  a  special 
endorsement  attached  to  the  public  liability  policy. 


lor  : 


INSURANCE 


NATURE  .OF    THE    CONTRACTS 

With  the  passenger  hazard  endorsement,  the  policy 
protects  the  owner  of  the  airplane  against  suits  arising 
from  injuries  sustained  by  the  public  while  riding  in  the 
plane.  The  rates  for  this  form  of  coverage  are  a  per- 
centage of  the  passenger  earnings,  with  a  minimum 
sum  per  passenger  trip.  The  maximum  limits  of  such 
a  policy  are  at  present  $10,000/130,000, — that  is,  the 
company  will  not  accept  a  responsibility  for  more  than 
$10,000  on  any  one  person  killed  or  injured  in  any  one 
accident,  nor  more  than  a  total  of  $30,000  in  case  sev- 
eral persons  are  involved  in  any  one  accident. 

Individual  accident  insurance  is  issued  in  the 
form  of  a  daily  ticket  policy,  which  becomes  applicable 
at  whatever  hour  the  flight  is  started  during  a  given 
day,  and  continues  until  four  o'clock  A.  M.  the  following 
day.  This  ticket  policy  is  for  the  principal  sum  of 
$5,000,  with  the  usual  indemnities  for  dismemberment 
and  loss  of  sight,  and  also  for  disabilities  of  a  temporary 
character.  Weekly  indemnities,  howeverr  apply  only 
where  the  holder  of  the  ticket  is  a  man.  Similar  tickets, 
with  the  weekly  indemnities  eliminated,  are  issued  to 
women.  This  ticket-policy  plan  has  been  developed 
so  that  a  similar  contract  may  be  issued  to  cover  a  trip 
of  any  proposed  duration, — including  a  round  trip,  if 
that  is  desired, — and  contracts  of  this  kind  are  called 
trip-ticket  policies.  The  rates  depend  upon  the  length 
and  character  of  the  trip,  and  at  present  are  largely 
matters  of  special  negotiation  in  individual  cases.  There 
are  also  means  provided 'for  obtaining  an  annual  per- 
sonal accident  policy,  carrying  a  rider  permitting  flight 
in  airplanes. 

Life  insurance  with  an  aircraft  permit  may  also  be 
obtained.  It  is  issued  in  one-vear  non-renewable 


104  AIRCRAFT    INSURANCE 

term  form  only,  and  an  extra  premium  in  addition  to 
the  term  rate  is  charged. 

It  really  matters  little  if  the  field  in  the  near  future 
is  to  be  restricted,  or  if  the  final  development  of  air- 
craft stops  at  a  point  short  of  making  it  a  necessity 
in  our  personal  and  commercial  lines.  The  airplane 
has  come  to  stay,  beyond  any  question,  and  its  future 
depends  largely  upon  the  preparation  made  for  its 
acceptance  and  regulation. 

The  Future  of  Aerial  Navigation:  In  the 
foregoing  pages,  the  requirements  for  successful  ae- 
rial navigation  have  been  discussed  at  length,  and 
they  are  of  utmost  importance.  We  may  assume  that 
airplanes  will  be  improved,  and  that  they  will  be  ren- 
dered more  stable,  more  dependable,  and  less  difficult 
of  operation.  Perhaps  they  will  be  much  less  expensive 
in  original  cost  and  subsequent  upkeep  in  the  near 
future,  but  all  this  will  be  of  little  avail  unless  aerial 
navigation  in  all  its  phases  is  made  the  subject  of 
constant,  careful,  rigid  supervision,  under  the  opera- 
tion of  well  devised  and  fully  enforced  laws. 

Our  former  allies,  as  well  as  our  former  enemies, 
are  far  ahead  of  us  in  the  development  of  aircraft,  and 
in  the  development  of  the  necessary  insurance  plans 
to  go  with  it.  It  is  freely  stated  that  England  is  to 
be  the  aircraft  center  of  the  world,  and  that  from 
England  will  come  the  insurance  plans  and  provisions 
in  the  various  lines  required,  and  without  which  aircraft 
projects  of  whatever  nature  cannot  succeed.  The 
United  States  ought  to  strive  to  at  least  divide  this 
honor  with  her  former  ally.  We  ought  to  make  it  our 
business  to  see  that  the  United  States  remains  on  the 
map  in  the  matter  of  aircraft  development.  The 


FUTURE    OF    AERIAL    NAVIGATION  105 

heavier-than-air  machine  was  born  in  the  United 
States.,  and  developed  here  to  a  certain  point,  but  it 
was  ignored  as  a  factor  of  any  value  by  the  people  at 
large.  Other  countries  took  up  the  projects  which  we 
neglected,  and  we  have  suffered  much  in  consequence. 
If  reconstruction  is  ever  accomplished,: — if  we  ever 
come  back  to  normal  times  and  to  a  normal  method  of 
living, — there  will  come  a  period  of  sharp  competition 
during  which  recourse  must  be  had  to  every  possible 
method  for  maintaining  our  position  in  our  own  mar- 
kets and  in  the  markets  of  the  world.  In  this  period 
aircraft  will  most  surely  play  its  part,  and  a  very 
important  part  too.  The  fact  that  we  here  in  the 
United  States  are  far  behind  England  and  all  other 
countries  in  the  development  of  this  most  helpful 
competitive  means  should  not  deter  us  from  laying  a 
sound  foundation  and  establishing  a  useful  practice  for 
aircraft  insurance, — notwithstanding  present  discour- 
agements, notwithstanding  a  limited  field,  and  not- 
withstanding the  lack  of  substantial  hope  for  the 
immediate  future. 

We  must  have  aircraft.  They  must  be  developed 
and  improved.  They  must  be  cheapened  in  cost  and 
up-keep.  They  must  be  dependable.  They  must  be 
practical.  They  must  do  their  part  in  the  annihilation 
of  space, — a  part  now  so  amply  played  in  the  trans- 
mission of  words  by  telegraph,  either  of  the  old  kind 
or  of  the  more  modern  sort.  Chicago  can  order  goods 
from  New  York  by  telegraph  or  telephone  in  a  few 
minutes,  but  New  York  cannot  deliver  the  goods  to 
Chicago,  by  the  means  now  at  hand,  with  sufficient 
promptness  to  meet  the  requirements  of  the  future. 
The  railroads  are  largely  impotent.  Steamships  are 


IO6  AIRCRAFT    INSURANCE 

not  always  available.  The  automobile  truck  has  its 
limitations,  and  certainly  aircraft  has  a  place.  We 
must  not  forget  these  things.  We  must  work  in  antici- 
pation of  the  future.  We  must  work  for  the  supremacy 
of  the  United  States  of  America  in  all  things  respecting 
her  commerce,  and  those  plans  for  commerce  which 
experience  has  demonstrated  to  be  feasible,  and  which 
probably  will  soon  be  regarded  as  necessary. 


GLOSSARY  OF  AVIATION  TERMS 


/N  preparing  this  section  we  have  endeavored  to  conform  as 
closely  as  practicable  to  the  terminology  given  in  Report  No.  91 
of  the  National  Advisory  Committee  for  Aeronautics , — "Nomencla- 
ture for  Aeronautics" — and  in  a  few  cases  we  have  adopted  the 
precise  language  of  that  report.  The  present  glossary  is  far  more  lim- 
ited in  scope  than  Report  No.  <?/,  however ,  because  we  have  compiled 
it  with  special  reference  to  the  probable  wants  of  readers  of  this  book. 


Aerodrome:       See  AIRDROME. 

Aerofoil:  A  flat  or  curved  winglike  structure,  so  designed 

and  disposed  that  the  air  through  which  it  moves 
will  react  against  its  surface.  The  part  of  an 
airplane  wing  against  which  the  supporting  action 
of  the  air  is  exerted.  Often  called  a  ''plane." 
(The  last  syllable,  "foil",  refers  to  the  fact  that  in 
the  earlier  forms,  at  all  events,  the  aerofoils  were 
quite  thin.) 

Aeroplane:        See  AIRPLANE. 

Aileron:  A  movable  auxiliary  surface,  usually  constituting 

part  of  the  trailing  edge  of  a  wing  to  which  it  is 
attached  by  a  hinge,  and  used  for  controlling  the 
rolling  motion  of  an  airplane.  (A  French  word, 
meaning  "a  small  wing  or  fin.") 

Aircraft:  Any  form  of  vehicle  used  in  navigating  the  air. 

Airdrome :  A  large,  permanent  flying  field, — usually  equipped 
with  hangars,  repair  shops,  and  a  supply  station. 
The  word  "aerodrome,"  from  which  "airdrome" 
is  derived,  was  originally  used  by  Langley  to 
designate  any  heavier-than-air  flying  machine  (of 
the  airplane  type),  which  is  propelled  by  its  own 
motive  power;  but  in  that  sense  it  has  become 
wholly  obsolete.  ("Aerodrome"  is  derived  from 
two  Greek  words  meaning  "air"  and  "running.") 


io8 
Airplane: 


Airscrew: 
Airship : 


Air-speed 
indicator: 


Alcohol : 


Altimeter: 


Anemo- 
meter : 


Angle  of 
attack: 

Angle  of 
incidence; 


Aspect 
ratio : 

Aviator : 


Axes  of  an 
aircraft : 


GLOSSARY 

A  form  of  aircraft,  heavier  than  air,  employing 
wing  surfaces  for  support,  and  containing  a  power 
plant  for  propelling  it  through  the  air.  (Usually 
employed  in  connection  with  machines  fitted  with 
landing  gear  suited  to  operation  from  the  land.) 
See  PROPELLER. 

An  elongated  lighter-than-air  machine,  propelled 
by  airscrews,  and  depending  for  its  buoyancy 
upon  a  large  bag  or  other  receptacle,  which  is 
filled  with  a  gas  lighter  than  air.  (Special  forms 
of  it  are  known  as  "dirigibles"  and  "blimps," 
and  by  other  names.) 

An  instrument  for  measuring  the  velocity  of  an 
aircraft  relatively  to  the  air  through  which  it  is 
moving. 

This  word,  when  used  without  any   qualifying 
adjective,  is  supposed  to  signify  ethyl  alcohol, 
or  grain   alcohol. 
(Compare    METHANOL.) 

An  instrument  for  indicating  the  height  of  an 
aircraft  above  the  surface  of  the  earth.  (Essen- 
tially an  aneroid  barometer.) 
An  instrument  used  for  measuring  the  velocity  of 
the  wind,  relatively  to  the  body  to  which  the 
anemometer  is  attached. 

The   acute   angle   between   the   direction  of  the 
relative  wind  and  the  chord  of  an  aerofoil. 
The  angle  that  a  chord  of  an  aerofoil  makes  with 
the  horizontal,  when  the  machine  is  in  a  flying 
position. 

The  ratio  between  the  spread  and  the  mean  chord 
of  an  aerofoil. 

Any  person  (of  either  sex)  who  practises  the  art 
of  flying  in  heavier-than-air  machines. 
Certain  imaginary  lines  of  reference,  fixed  with 
respect    to    the    aircraft,    and   passing    through 
its    center    of   gravity.     They    include    (i)    the 


GLOSSARY 


109 


longitudinal  or  fore-and-aft  axis,  lying  in  the 
plane  of  symmetry  and  usually  running  in  a 
direction  parallel  to  the  axis  of  the  propeller; 
(2)  the  normal  axis  (sometimes  called  the  vertical 
axis),  also  lying  in  the  plane  of  symmetry  but 
running  in  a  direction  perpendicular  to  the 
longitudinal  axis;  and  (3)  the  lateral  (or  athwart- 
ship)  axis,  running  perpendicularly  to  the  plane 
of  symmetry  and  intersecting  the  other  two  axes 
at  the  center  of  gravity  of  the  machine. 

Back-wash:  A  stream  of  disturbed  air  in  the  wake  of  an  air- 
plane. This  is  also  referred  to  as  the  "slip- 
stream." 

Bank:  To  rotate  an  airplane  through  a  limited  angle 

about  its  fore-and-aft  axis,  so  that  one  wing 
becomes  lower  than  the  other.  To  "right  bank" 
is  to  incline  the  right  wing  downward. 

Barograph:  An  instrument  used  for  recording  barometric 
pressures  or  altitudes. 

Bay:  The  cubic  space  lying  between  two  transversely 

adjacent  pairs  of  struts  in  the  truss  of  an  airplane 
wing.  The  bay  nearest  the  center  of  the  machine 
is  known  as  the  first  bay. 

Biplane:  A  form  of  airplane  having  two  sets  of  supporting 

surfaces,  one  above  the  other. 

Blade:  The  paddle-shaped  portion  of  a  propeller,  outside 

of  the  boss  or  hub.  The  working  surface,  or  side 
against  which  the  air  thrust  operates  (and  which 
is  nearly  flat),  is  the  face  of  the  blade,  and  the 
opposite,  strongly-convex  side  is  the  back. 

Blinker:  See  NON-SKID. 

Body:  In  an  airplane  or  seaplane,  the  boat-like  portion 

that   carries   the   passengers,   pilot,   freight,   etc. 

(Compare  FUSELAGE  and  NACELLE.) 

Boss:  The  hub,  or  central  portion,  of  a  propeller  screw. 

Camber:  The  rise  or  convexity  of  the  curve  of  an  aerofoil 

from   its   chord,  usually  expressed   as   the   ratio 


I  IO 


GLOSSARY 


Capacity: 

Carrying 

capacity: 

Ceiling: 


Center  of 
pressure : 

Chassis: 

Chord  of  an 
aerofoil 
section : 


Control 
column : 


Control- 
stick: 


Controls: 


between   the  maximum  departure  of  the   curve 
from    the   chord   and   the   length   of  the   chord. 
(This  term  has  long  been  used  in  a  similar  sense 
in  connection  with  bridge  construction.) 
Same  as  LOAD. 

See  LOAD. 

The  absolute  ceiling  is  the  limiting  altitude 
(measured  from  sea-level),  above  which  a  given 
aircraft  is  incapable  of  maintaining  flight.  The 
service  ceiling  is  the  height,  similarly  measured, 
above  which  a  given  aircraft  cannot  rise  at  a  rate 
exceeding  a  certain  small  given  limit, — this  speci- 
fied limit  being  100  feet  per  minute  in  the  .United 
States  Air  Service. 

The  point  on  any  given  aerofoil  or  aerofoil  chord, 
through  which,  at  any  instant,  the  line  of  action 
of  the  resultant  air  pressure  passes. 
See  LANDING  GEAR. 

A  straight  line,  parallel  to  the  central  plane  of 
symmetry  of  the  machine,  and  tangent  at  the 
front  and  rear  to  the  under  curve  of  an  aerofoil 
section.  The  "length  of  the  chord"  is  the  width 
of  the  aerofoil  as  projected  on  the  chord.  (If 
the  aerofoil  has  a  doubly  convex  camber,  the 
chord  is  understood  to  be  the  straight  line  joining 
the  leading  and  trailing  edges,  and  the  length  of 
the  chord  is  then  taken  to  be  the  distance  between 
these  two  edges.) 

A  control  lever  with  a  rotatable  wheel  mounted  at 
its  upper  end.     The  elevators  are  operated   by 
the  fore  and  aft  movement  of  the  column  and  the 
ailerons  are  actuated  by  rotating  the  wheel. 
The  vertical  lever  by  which  certain  of  the  principal 
controls   in   an   airplane   are   operated.     This   is 
sometimes  called  the  "joy-stick." 
A  general  term  applied  to  the  apparatus  provided 
to  enable  the  pilot  to  regulate  the  speed,  direction 


GLOSSARY 


III 


Diving 
rudder: 

Dope: 
Drag: 


of  flight,  attitude,  altitude,  and  power  of  an 
aircraft. 

Critical  The  angle  of  attack  at    which  the  flow  of  air 

angle:  about  an  aerofoil  changes  abruptly.     An  aerofoil 

may  have  two  or  more  such  critical  angles,  and 
one  of  them  usually  corresponds  to  the  position  at 
which  the  lift  of  the  airplane,  in  sustained  flight, 
is  greatest. 

Decalage:  The  angle  between  the  chords  of  the  principal 

planes  and  the  horizontal  tailplanes.  (This  is 
also  known  as  the  "Longitudinal  V.") 

Dihedral  The  main  supporting  surfaces  of  an  airplane  are 

angle:  said  to  have  a  dihedral  angle  when  both  right  and 

left  wings  are  upwardly  or  downwardly  inclined 
to  a  horizontal  transverse  line.  The  -angle  is 
measured  by  the  inclination  of  each  wing  to  the 
horizontal.  If  the  inclination  is  upward,  the 
angle  is  said  to  be  positive;  if  downward,  nega- 
tive. The  several  main  supporting  surfaces  of  an 
airplane  may  have  different  amounts  of  dihedral. 
Same  as  ELEVATOR. 

The  special  varnish  used  for  coating  the  cloth 
surfaces  of  airplane  members,  to  render  them  taut, 
airtight,  and  waterproof. 

The  component,  parallel  to  the  relative  wind,  of 
the  total  force  on  an  aerofoil  or  aircraft  due  to  the 
air  through  which  it  moves.  That  part  of  the 
drag  due  to  the  wings  is  called  "wing  resistance," 
and  that  due  to  the  rest  of  the  airplane  is  called 
"structural"  or  "parasite  resistance." 

Drag  wires:  Cables  used  to  prevent  the  horizontal  pressure  of 
the  wind  from  folding  the  wings  of  an  airplane 
backward.  These  are  also  known  as  drift  wires. 

Drift:  The  angular  deviation  from  a  set  course  over  the 

earth,  due  to  cross  currents  of  wind. 

Drift  wires:       See  DRAG  WIRES. 

Elevator:  A  hinged  auxiliary  surface,  usually  attached  to  the 


112 


GLOSSARY 


Emergency 
field: 

Empennage 


Engine, 
right  or 
left-handed 


Engine 
bearers: 


Entering 
edge: 

Factor  of 
safety: 


Fins: 


Flight 
path: 

Float  (or 
Pontoon) 


Flying 
boat: 


tail  plane,  and  used  for  controlling  the  attitude 
of  an   aircraft   with  respect   to  its   athwartship 
axis, — that  is,  for  imparting  a  pitching  motion  to 
the  machine,  or  for  counteracting  such  motion. 
A  small  landing  field,  for  use  in  case  of  a  forced 
landing.     (Compare   AIRDROME.) 
Same  as  TAIL.     (Derived  from  the  French  word 
"penne,"    a    feather,    in    reference    to    the    tail- 
feathers  of  a  bird.) 

The  distinction  depends  upon  the  direction  of 
rotation  of  the  output  shaft.  If,  when  viewed 
from  the  output  shaft  end,  the  shaft  rotates 
counter-clockwise,  the  engine  is  said  to  be  right- 
handed.  If  the  rotation  is  clockwise  when  the 
shaft  is  thus  viewed,  the  engine  is  left-handed. 
The  rails,  beams,  or  fuselage  members  which 
bear  the  weight  of  the  engine,  and  to  which  the 
engine  is  bolted. 

The  foremost  edge  of  an  aerofoil. 
The  ratio  that  the  ultimate  strength  of  any  part 
bears  to  the  maximum  stress  to  which  that  part 
may  be  subjected  in  the  course  of  normal  opera- 
tion. Thus  if  the  stress  that  would  be  required  in 
order  to  produce  rupture  is  ten  times  as  great 
as  the  maximum  working  stress,  the  part  is  said 
to  have  a  factor  of  safety  of  ten. 
Small  fixed  plane  surfaces,  attached  to  various 
parts  of  aircraft  for  the  purpose  of  promoting 
stability,  and  projecting  in  a  way  suggestive  of 
the  fins  of  a  fish. 

The  path  of  the  center  of  gravity  of  an  aircraft, 
with  reference  to  the  surface  of  the  earth. 
That  portion  of  a  seaplane  which  provides  buoy- 
ancy when  the  machine  is  resting  on  the  surface 
of  the  water. 

A   seaplane   having   a   boat-shaped   body   which 
serves  as  a  float  when  the  machine  is  resting  on  the 


GLOSSARY  113 

water.  (Flying  boats  are  often  provided  with 
additional  auxiliary  floats  or  pontoons.) 

Foot  bar:  A  pivoted  bar,  by  which  the  pilot  operates  the 

rudder  of  his  machine.  - 

Fuselage:  The  elongated  boat-like  housing  of  an  airplane, 

which  contains  the  passengers  and  usually 
considerable  of  the  mechanism  also.  It  is 
approximately  streamlined  in  form,  and  takes  its 
name  from  the  French  word  "fuseler,"  meaning 
"to  taper." 

Gap:  The  shortest  distance  between  the  planes  of  the 

chords  of  the  upper  and  lower  wings  of  a  biplane, 
measured  along  a  line  perpendicular  to  the  chord 
of  the  upper  wing  at  any  designated  point  of  its 
entering  edge. 

Glide :  To  descend  at  a  normal  angle  of  attack  without  the 

aid  of  the  engine, — the  necessary  flying  speed 
being  maintained  by  the  action  of  gravity. 
(Gliding  is  often  called  volplaning.) 

Gliding  The  angle  that  the  flight  path  makes  with  the 

angle:  horizontal,  when  gliding  toward  the  earth  under 

the  influence  of  gravity  alone. 

Guy:  A  rope,  chain,  cable,  wire,  or  rod,  attached  to  an 

object  to  guide  or  steady  it,  or  to  hold  it  in  posi- 
tion. 

Hangar:  A  shed  for  housing  aircraft.     (A  French  word 

signifying  a  shed,  shanty,  or  lean-to.) 

Head  The  total  resistance  (in  the  direction  of  the  longi- 

resistance:  tudinal  axis  of  the  machine)  that  is  offered  by  the 
air  to  the  normal  forward  motion  of  an  aircraft 
and  its  passengers  or  other  contents. 

Helicopter:  A  form  of  aircraft  deriving  its  lifting  or  sustaining 
power  from  the  direct  vertical  thrust  of  large 
downwardly-directed  propellers.  Machines  of 
this  type  are  not  in  actual  use,  but  some  authori- 
ties consider  that  the  idea  is  capable  of  practical 
development.  (The  name  is  derived  from  two 


H;4 

Horn: 

Hydro- 
airplane: 

Inclino- 
meter: 

Joy-stick: 
Land  plane: 

Landing 
gear: 


Lateral 
stability: 

Leading 
edge: 

Lift: 


Lifting 
capacity: 

Limiting 
height: 

Load : 


Longeron : 


GLOSSARY 

Greek  words,  signifying  "spirally-acting-wing.") 
A  short  projection,  often  horn-like  in  form,  secured 
to  a  movable  part  of  an  airplane  and  serving  as  a 
lever  arm  in  controlling  that  part. 

A  seaplane  fitted  with  a  landing  gear  of  pontoons. 

An  instrument  for  measuring  the  angle  between 

any  axis  of  an  aircraft  and  the  horizontal. 

A    colloquial    expression    used    to   designate    the 

control-stick. 

An  airplane  having  landing  gear  for  operating 

from  the  land.     (Compare  SEAPLANE.) 

The  understructure  of  an  aircraft,  including  all 

those  parts  which  are  designed  to  support  the 

machine  when  it  is  not  in  flight,  and  to  enable 

it   to  alight  in  safety  when   making  a   landing. 

(Also  known  as  the  "chassis," — a  French  word 

meaning  a  "framework"  or  "housing.") 

Stability   with   reference    to   rotation   about   the 

longitudinal  axis. 

Same  as  ENTERING  EDGE. 

The  component  of  the  total  air  force  that  is 
perpendicular  to  the  relative  wind  and  in  the 
plane  of  symmetry. 

Same  as  LOAD. 

See  CEILING. 

The  total  maximum  weight  that  an  aircraft  is 

capable    of    supporting    in    flight.     The    useful 

load  (sometimes  called  the  "carrying  capacity") 

is   the  maximum  weight   that   the  machine  can 

support  in  addition  to  its  own  weight  and  that  of 

the  various  instruments  that  are  essential  to  its 

proper  management. 

A  fore-and-aft  member  of  the  body-frame  or  float. 

(Also  called  a  "longitudinal.") 


GLOSSARY 


Longi- 
tudinal: 

Longitu- 
dinal 
stability: 

Methanol: 


Monoplane 
Multiplane 

Nacelle: 
Non-skid: 


Nose  dive: 

Orni- 
thopter : 


Pancake : 


Parachute: 


Pilot: 


See  LONGERON. 

Stability  with  respect  to  pitching, — that  is,  with 
respect  to  rotation  about  the  athwartship  axis. 
(See  STABILITY,  and  AXES  OF  AN  AIRCRAFT.) 
The  substance  commonly  known  as  methyl 
alcohol  or  wood  alcohol.  (The  American  Chemical 
Society  has  recommended  the  adoption  of  this 
word,  to  avoid  confusion  with  grain  alcohol;  and 
we  have  followed  that  counsel  in  the  present 
book.) 

A  form  of  airplane  deriving  its  support  from  a 
single  wing  on  each  side  of  the  body. 
A  form  of  airplane  employing  more  than  two  sets 
of  main  supporting  surfaces,  superposed.     (Com- 
pare BIPLANE  and  MONOPLANE.) 
The  body  portion  of  a  pusher-type  airplane,  or, 
the  car  of  a  dirigible.    (In  French,  the  word  means 
"a   little    boat.") 

An  auxiliary  vertical  plane,  sometimes  placed 
upon  or  between  the  wings  of  an  airplane  to 
check  side-slipping.  (Also  called  a  "blinker.") 

A  dangerously  steep  head-on  descent. 

A  form  of  aircraft  deriving  its  propelling  force  and 
support  from  wings  that  flap  similarly  to  those  of 
a  bird.  Machines  of  this  type  are  not  yet  prac- 
ticable. (The  name  is  derived  from  two  Greek 
words  signifying  "bird  wings.") 

To  descend  vertically,  or  along  a  very  steep  course, 
with  the  wings  of  the  machine  nearly  horizontal. 
(The  name  bears  reference  to  a  fancied  analogy 
with  the  ilatwise  fall  of  a  pancake.) 

An   umbrella-like   appliance   used   to   retard   the 
descent  of  ji  falling  body,  and  particularly  of  a 
person.     (From     two     Greek     words     signifying 
"to  ward  off  a  fall.") 
A  person  qualified  to  operate  an  aircraft. 


Il6  GLOSSARY 

Pitch:  The  geometrical  pitch  of  an  airscrew  or  propeller 

is  the  distance  it  would  travel  forward,  in  one 
revolution,  if  it  were  turning  in  a  medium  that 
would  allow  of  no  slipping.  The  effective  pitch 
is  the  distance  the  airplane  advances,  in  actual 
flight,  in  the  course  of  one  revolution  of  the 
propeller.  The  difference  between  the  geometric- 
al pitch  and  the  effective  pitch  is  called  the  slip 
of  the  propeller. 

Plane:  See  AEROFOIL.  (The  word  "plane"  is  often 

used,  also,  as  an  abbreviation  for  "airplane"  or 
"volplane.") 

Plywood:  A  structural  material  made  by  gluing  together  a 

number  of  layers  of  wood  veneer,  with  the  grain 
of  the  several  layers  running  in  different  direc- 
tions. 

Pontoon:  See  FLOAT. 

Propeller:  A  screw  so  mounted  on  an  airplane  that  its 

rotation  moves  the  machine  through  the  air. 

Pusher  An  airplane  in  which  the  propeller  is  located  back 

airplane:  Of  the  wings,  so  that  it  pushes  the  machine  from 

behind.  (Compare  TRACTOR  AIRPLANE.) 

Pylon :  A  mast  or  post. 

Race  of  an 

airscrew:  The  air-stream  delivered  by  a  revolving  propeller. 

Relative  The  motion  of  the  air  relatively  to  the  airplane. 

wind:  The  direction  and  speed  of  the  relative  wind 

depend  (i)  upon  the  direction  and  speed  of  the 
actual  wind  as  perceived  by  a  stationary  observer, 
and  (2)  upon  the  direction  and  speed  of  the  mo- 
tion of  the  airplane  itself. 

Resistance:       See  HEAD  RESISTANCE. 

Rib:  A  fore-and-aft  member  of  the  wing,  used  to  give 

form  to  the  wing-section,  and  to  serve  as  a  support 
for  the  wing  covering. 

Roll:  To  incline  an  airplane  laterally.     The  angle   of 

roll  is  the  angle  through  which  an  aircraft  must 


GLOSSARY 


117 


Rudder: 


Seaplane 


Side  slip: 


Side 
slipping: 

Skidding 


Skids: 


Skis: 
Slip: 

Slip- 
stream: 

Spar: 
Spin: 


rotate  on  its  longitudinal  axis  in  order  to  bring  its 
lateral  axis  into  the  horizontal  plane. 
A  flat  or  streamlined  surface,  hinged  or  pivoted, 
and  used   for   controlling   the   movement  of  an 
aircraft  about  its  vertical  axis. 
A  special  form  of  airplane,  designed  for  operating 
from  the  surface  of  the  water.     (The  term  "water 
plane"  is  passing  out  of  use,  the  word  "seaplane" 
being  preferred,  whether  the  machine  is  to  operate 
from  the  ocean  or  from  rivers  and  lakes.) 
A  sidewise  and  downward  motion  of  an  airplane, 
taking  place  at  right  angles  to  the  normal  direc- 
tion of  flight,  in  such  a  way  that  the  wings  of  the 
airplane  move  through  the  air  edgewise  or  nearly 
so. 

Sliding  toward  the  center  of  a  turn,  on  account  of 
banking  too  steeply,  or  in  consequence  of  having 
too  low  a  flying  speed.  (Compare  SKIDDING.) 
Sliding  sidewise  and  away  from  the  center  of  a 
turn,  on  account  of  insufficient  banking.  (Com- 
pare SIDE  SLIPPING.) 

Long  metal  or  wooden  runners  fitted  to  an  air- 
plane,   and    designed     to    prevent    nosing-over 
when  landing,  or  to  protect  the  wings  from  contact 
with  the  ground,  or  to  support  the  tail  of  the 
machine.     (Also  applied  to  a  ski-form  of  landing 
gear,  which  is  used  on  snow.) 
Same  as  SKIDS. 
See  PITCH;   SIDESLIP;   SIDESLIPPING;  SKIDDING. 

Same  as  BACK-WASH. 
See   WING  SPAR. 

An  aerial  manoeuver  consisting  of  a  combination 
of  roll  and  yaw,  with  the  longitudinal  axis  of  the 
airplane  inclined  steeply  downward.  The  air- 
plane descends  in  a  helix  of  large  pitch  and  small 
radius,  the  upper  side  being  inside  of  the  helix 


u8 


GLOSSARY 


and  the  angle  of  attack  on  the  inner  wing  being 
maintained  at  an  extremely  large  value. 

Spread :  The  maximum  width  of  an  airplane,  as  measured 

from  tip  to  tip  of  the  wings. 

Stability:  An  airplane  is  said  to  possess  stability  if,  after 

being  subjected  to  a  small  disturbance  of  any 
kind  during  steady  flight,  it  tends  to  return 
quickly  and  automatically  to  a  similar  steady 
state.  Various  kinds  of  stability  are  recognized, 
according  to  the  nature  of  the  disturbance.  For 
example,  the  machine  may  or  may  not  be  stable 
with  regard  to  rolling,  yawing,  pitching,  or  mo- 
tions of  other  specified  kinds;  and  it  may  be 
stable  with  respect  to  a  disturbance  of  one  of 
these  kinds,  but  unstable  with  regard  to  another 
one. 

Stabilizer:  Specifically  and  most  commonly,  the  stationary 
horizontal  tail  surface  of  an  airplane.  The  name 
is  also  applied,  however,  to  any  mechanical 
device  the  purpose  of  which  is  to  insure,  or  increase, 
stability  in  flight. 

Stagger:  The  amount  by  which  the  entering  edge  of  the 

upper  wing  of  a  biplane,  triplane,  or  multiplane 
projects  beyond  the  entering  edge  of  a  lower  wing, 
— usually  expressed  as  percentage  of  gap. 

Stagger  Wires  used  for  maintaining  the  stagger   of  the 

wires:  wings. 

Stalling:  The  losing  of  the  speed   (relatively  to  the  air) 

that  is  essential  to  the  proper  control  of  an  air- 
craft. 

Statoscope:  An  instrument  for  detecting  or  registering  small 
changes  in  altitude. 

Stay:  A  wire,  cable,  rope,  or  rod,  used  for  holding  parts 

together,  or  for  contributing  stiffness. 

Step:  A  step-like  break  or  discontinuity  of  form  on  the 

bottom  of  a  float  or  hull,  designed  to  modify  the 
dynamic  reaction  from  the  water. 

Stick:  Same  as  CONTROL-STICK. 


GLOSSARY  119 

Streamline:  The  path  followed  by  any  given  particle  of  air, 
in  a  current  that  is  flowing  (or  streaming)  around 
a  solid  object.  The  object  may  be  fixed  and  the 
air  moving,  or  the  object  may  be  moving  while 
the  air  is  stationary  (save  for  the  local  dis- 
turbance that  the  object  produces).  In  either 
case  the  streamlines  are  supposed  to  be  the  lines  of 
flow  of  the  air,  as  they  appear  to  an  observer  who 
is  fixedly  associated  with  the  solid  object.  The 
word  "streamline"  is  usually  understood  to  refer 
to  streaming  motions  that  are  not  attended  by 
the  production  of  eddies.  Eddy-formation  in- 
volves the  expenditure  of  energy,  and  as  the 
energy  so  expended  is  wholly  wasted,  it  is  desirable 
to  give  every  part  of  the  airplane  a  streamline 
form  (or  section)  so  that  the  air  will  flow  around  it 
without  producing  eddies. 

Strut:  A  compression  member  of  a  truss  frame;  specific- 

ally  and   most   commonly,   one   of  the   vertical 
members  of  a  wing  truss  in  a  biplane. 

Sweep-  The  angle  between  the  lateral  axis  of  an  airplane 

back:  and  the  entering  edge  of  the  main  plane,  measured 

in  a  plane  parallel  to  the  lateral  axis,  and  to  the 

chord  of  the  main  plane. 

Tail:  The  rear  portion  of  an  airplane,  including  the 

rudder,  elevators,  and  fins. 

Tail  plane:  A  stationary  horizontal  (or  nearly  horizontal)  tail 
surface,  used  to  stabilize  the  plane  with  regard  to 
pitching  motions.  This  surface  is  often  called 
a  "stabilizer." 

Tandem  An  airplane  having  two  sets  of  wings,  one  behind 

plane:  the  other. 

Torque  of  a       The    torsion    to    which    the    propeller    shaft    is 

propeller:          subjected  when   the  engine  is  in   motion;    the 

tendency  of  the  propeller  to  cause  an  airplane  to 

revolve  about  its  longitudinal  axis,  in  a  direction 

opposite  to  that  in  which  the  propeller  is  turning. 


120 


GLOSSARY 


Tractor 
airplane : 


Trailing 
edge: 

Triplane: 
Truss: 


Under 
carriage: 

Useful  load 
Volpique : 


Volplane: 
Warp: 


Water 
plane: 

Wing: 


Wing 
loading: 

Wing  rib: 
Wing  spar; 


Wood 
alcohol : 


An  airplane  having  its  propeller  situated  in  front 
of  the  wings,  so  that  the  machine  is  pulled  through 
the  air.  The  propeller  of  such  an  airplane  is 
often  called  a  "tractor  screw"  or  "tractor  air- 
Compare  PUSHER  AIRPLANE.) 


screw. 


The  rearmost  portion  of  an  aerofoil. 
An  airplane  having  three  pairs  of  main  support- 
ing surfaces  or  wings,  superposed. 
The  framework  by  which  the  load  sustained  by 
the  wings  of  an  airplane  is  transmitted  to  the  body 
of  the  machine. 

Same  as  LANDING  GEAR. 

See  LOAD. 

Same  as  NOSE  DIVE.     (From  two  French  words, 

"vol"     and     "pique",     signifying,     respectively, 

"flight"  and  "beak"  or  "prow.") 

Same  as  GLIDE. 

To  change  the  form   of  a  wing  by  bending  or 

twisting  it,   by  means  of  controls  provided  for 

that  purpose.    , 

See  SEAPLANE. 

That  part  of  the  main  supporting  surface  of  an 
airpla-ne  which  lies  on  one  side  of  the  body  or 
fuselage.  Thus  a  monoplane  has  two  wings,  and 
a  biplane  has  four. 

The  weight  carried  per  unit  area  of  supporting 
surface. 

Same  as  RIB. 

A  stiffening  chord  or  member  in  a  wing,  running 
athwartship; — /.  <?.,  lengthwise  of  the  wing. 

Called  "methanol"  in  the  present  book. 
(See  METHANOL.) 


Yaw:  To   swing   an   airplane   about   its   vertical 


axis 


GLOSSARY  121 

The  "angle  of  yaw"  is  the  angle  between  the 
direction  of  the  relative  wind  and  the  plane  of 
symmetry  of  an  aircraft.  It  is  positive  when  the 
aircraft  turns  to  the  right. 

Zoom:  To  climb  for  a  few  moments  at  a  steeper  angle 

than  can  be  maintained  in  continuous  flight. 


INDEX 

Accidents,  general  causes  of,  43 

what  to  do  in  case  of,  55. 

— See  also  Pilots,  errors  of;  Airplanes,  failure  of;  Fire,  a  cause  of 
accidents. 

Acetone,  toxic  effects  of,  74. 
Aerial  Experiment  Association,  8. 
laws,  need  of,  86. 
navigation,  the  future  of,  104. 
transportation,  dangers  of,  95. 

speed  claimed  for,  94. 
Aeronautics,  the  future  of,  11. 

— See  also  Aviation, 
Ailerons,  function  of,  23,  29. 

— See  also  Control  surfaces. 
Aircraft,  commercial  uses  of,  11. 

types  of,  13. 
Airdrome,  an  ideal,  79. 

personnel  needed  in,  84. 
specifications  for  an,  81. 
Airplane,  beginnings  of  the,  6. 
Airplanes,  all-metal. — See  Duralumin. 
failure  of,  47. 
procedure  in  repairing,  68. 
reliability  of,  97. 
cost  of,  98. 

structural  parts  of,  18. 
structural  materials  used  in,  25. 
types  and  classification  of,  15,  18 
— See  also  Seaplanes. 
Airships,  types  of,  13. 
Air-speed  indicator,  53. 
Airways,  definition  of,  85. 
Altimeter,  types  of,  53. 


124  INDEX 

Aluminum  employed  in  airplanes,  26. 
Ambulance,  use  of,  in  airdromes,  55. 
Amyl  acetate,  effects  of,  on  the  human  system,  74. 

alcohol,  poisonous  effects  of,  75. 
Automatic  sprinklers,  use  of  in  airplanes,  48. 
Aviation,  the  development  of,  in  the  United  States,  9. 

Balloon,  first  ascent  of  human  being  in  a,  4. 
Balloons,  early,  3. 

in  America,  early  experiments  with,  5. 

used  for  observation  work,  5,  12. 
Balsa  wood,  for  stream-lining  interplane  struts,  26. 
Benzol  vapors,  effects  of,  on  human  body,  74. 
Bronze,  used  in  airplanes,  26. 

Cables,  inspection  of,  37. 

method  of  running,  30. 
Camber,  in  airplane  wings,  32. 

Carburetor,  arrangement  of  intake  to  prevent  fires,  48. 
Charles,  J.  A.  C.,  a  French  physicist,  3,  5. 
Chassis. — See  Landing  gear. 
Clothing,  special,  for  aviators,  41. 
Compass,  magnetic,  53. 
Control,  points  of,  in  airplanes,  29. 

stick,  function  of,  29. 

surfaces,  inspection  of,  38. 

Daedalus  and  Icarus,  1. 

Design  of  an  airplane  and  effect  of  on  performance,  31. 
Dirigibles. — See  Airships. 
Dope,  airplane,  nature  of,  73. 
purpose  of,  20. 

suggestions  as  to  kinds  to  use,  75. 
fire  resistive,  use  of,  on  airplanes,  51. 
Doping,  dangers  associated  with,  73. 

how  it  should  be  carried  on,  75. 
rooms,  exhaust  systems  for,  75. 
Drag  wires,  21. 

Duralumin,  use  of,  in  airplanes,  26. 
heat  treatment  of,  27. 

Elevator,  24,  29. 

— See  also  Control  surfaces. 
Emergency  fields,  85. 

stations,  need  of,  on  landing  fields,  55. 
Empennage. — See  Tail. 


INDEX  125 


Engines,  aeronautical,  cleaning  in  repair  shops,  77. 

desirable  points  in  design  of,  34. 

inspection  of,  39. 

testing  of,  78. 

types  of,  18. 

warming  up,  40. 

when  to  overhaul,  67. 
Exhaust  systems,  kind  to  be  used  in  doping  rooms,  75. 

Fabric. — See  Wing  covering. 
Fatigue,  effect  of,  on  a  pilot,  45. 
Fear  as  a  cause  of  accidents,  46. 
Feed-pipes,  importance  of  inspecting,  47. 

location  and  design  of,  34. 
Fin,  tail,  24. 

Fire,  a  cause  of  airplane  accidents,  47. 
prevention  of  in  airplanes,  47. 

in  repair  shops,  70. 
patrol,  aircraft  for,  12. 
Flying  boat. — See  Seaplanes. 

wires,  21. 
Fuselage,  19. 

drainage  of,  to  prevent  fires,  47. 

Gas. — See  Hydrogen. 

Gasoline,  supply  system,  need  of  inspecting  entire,  47. 

tanks,  safety  type  of,  to  prevent  fires,  50. 
Glue,  use  of,  in  repairing  airplanes,  72. 
Goggles,  the  need  of,  in  flying,  41. 
Gyroscope. — See  Stabilizers,  gyroscopic. 

Head,  loss  of,  associated  with  fatigue,  45. 
resistance,  effect  of,  on  landing,  33. 
Helicopter,  15. 

Hydroairplane. — See  Seaplanes. 
Hydrogen  gas  for  balloons,  early  use  of,  3. 

Icarus,  the  legend  of,  1. 
Incidence,  proper  angle  of,  33. 

wires,  21. 
Inclinometer,  53. 

Inspection  of  airplane,  how  to  make  an,  36. 
Instruments,  importance  of,  in  aerial  navigation,  52. 
Insurance,  aircraft,  limitations  of  field  for,  91. 

making  rates  for,  96. 

nature  of  contracts  for,  101. 

reasons  why  it  is  written,  99. 


126  INDEX 

Joy  stick. — See  Control  stick. 

Judgment,  a  lack  of,  causes  accidents,  45. 

Kilns,  location  of,  in  repair  shops,  72. 

Landing  gear,  construction  of,  24. 

inspection  of,  38. 
Landing  fields,  classification  of,  79. 

equipment  of,  for  night  flying,  83. 
need  of  legal  regulations  in,  86. 
wires,  21. 
Langley  "Aerodrome",  7. 

Dr.  Samuel  Pierpont,  a  pioneer  in  aeronautics,  6,  7. 
Legend  of  Icarus,  the,  1. 
Lift,  characteristics  affecting,  in  an  airplane,  32. 

Machine  shop,  hazards  in,  77. 

Magnetos,  protection  of,  to  prevent  fires,  48. 

Mail  service  by  airplanes,  11. 

Markers  for  use  on  landing  fields,  81. 

Methanol,  poisoning  effects  of,  74! 

Montgolfier,  first  successful  air  navigator,  3,  4. 

Motors. — See  Engines. 

Nacelle,  19. 

Orientator,  use  of,  in  training  pilots,  61. 
Ornithopter,  13. 

Paint,  fire  resistive,  use  of,  on  airplanes,  51. 
Pilots,  care  of  health  of,  64. 

errors  of,  45. 

examination  of,  63. 

granting  license  to,  63. 

necessary  qualifications  of,  58. 

need  of  legal  regulation  in  regard  to  licensing,  57,  88. 

training  of,  61. 

validity  of  license,  64. 
Propellers,  variable-pitch,  use  of,  52. 
"Pusher",  definition  of,  18. 

Radio-direction-finder,  importance  of,  in  aerial  navigation,  54 
Repair  shops,  equipment  needed  in,  67. 

hazards  in,  69. 

Rozier  the  first  human  being  to  ascend  in  a  balloon,  4. 
Rudder,  24,  29. 


INDEX  127 


Safety,  factor  of,  in  airplanes,  34. 

straps,  importance  of,  54. 
Seaplanes,  classification  of,  17. 
Shock  absorbers,  purpose  of,  25. 
Speed  of  an  airplane,  32. 
Stability  in  an  airplane,  31. 
Stabilizer,  gyroscopic,  30. 
horizontal,  24. 
vertical. — See  Fin. 

Steel,  use  of,  in  airplane  construction,  26. 
Struts,  inspection  of,  37. 

interplane,  21. 

Superchargers,  use  of,  in  high  altitudes,  52. 
Surgeon  should  be  employed  at  airdromes,  55. 

Tail,  23. 

skid,  inspection  of,  38. 
Tetrachlorethane,  a  dope  solvent,  73. 

poisonous  nature  of,  74. 
"Tractor,"  definition  of,  18. 
Transportation,  development  of  means  of,  92. 
Turnbuckles,  safe  features  of,  23. 

War.— See  World  War. 

Waste,  disposition  of,  in  doping  rooms,  76. 

Waste,  removal  of,  to  prevent  fire  in  workshops,  71. 

Weather  Bureau,  upper  air  investigation  by,  90. 

forecast  obtained  for  aviators,  89. 
Wind-cone,  use  of,  to  indicate  wind  direction,  82. 
Wing  covering,  nature  of,  20,  29. 
inspection  of,  36. 
ribs,  20. 
„    skids,  inspection  of,  37. 

spars,  19. 

Wings,  principal  parts  of,  19. 
Wires,  in  airplane  wings,-  21. 

inspection  of,  in  airplanes,  37. 
Wood,  uses  of,  in  airplane  construction,  25. 
World  War,  influence  of  the,  on  aeronautics,  9. 
Wright  Brothers,  early  experiments  of,  7,  8. 


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